J. C. Portal

Publication List Details

Period

1989 - 2009

Number

242

Co-Authors

High order fractional microwave induced resistance oscillations in 2D systems (2009)

Wiedmann, S., Gusev, G. M., Raichev, O. E., Bakarov, A. K., Portal, J. C.

We report on the observation of microwave-induced resistance oscillations associated with the fractional ratio n/m of the microwave irradiation frequency to the cyclotron frequency for m up to 8 in a...

Quantum interference of magnetic edge channels activated by intersubband optical transitions in magnetically confined quantum wires (2009)

Nogaret, Alain, Portal, J. C., Beere, H. E., Ritchie, D. A., Phillips, C.

We investigate the photoresistance of a magnetically confined quantum wire in which microwave-coupled edge channels interfere at two pinning sites in the fashion of a Mach-Zehnder interferometer. The...

Interference oscillations of microwave photoresistance in double quantum wells (2008)

Wiedmann, S., Gusev, G. M., Raichev, O. E., Lamas, T. E., Bakarov, A. K., Portal, J. C.

We observe oscillatory magnetoresistance in double quantum wells under microwave irradiation. The results are explained in terms of the influence of subband coupling on the frequency-dependent...

Studies of Skyrmions at ν=1 in the Limit of Zero g-factor. (2008)

D. R. Leadley, R. J. Nicholas, D. K. Maude, A. N. Utjuzh, J. C. Portal, J. J. Harris, ...

In a two-dimensional electron gas at ν=1 (where the filling factor ν=neh/eB measures how many Landau levels (LL) are filled) the ground state should be regarded as a ferromagnet since all the spin...

FRACTIONAL QUANTUM HALL EFFECT MEASURED IN A SPIN DEGENERATE ELECTRON GAS (2008)

D. R. Leadley, R. J. Nicholas, D. K. Maude, J. C. Portal, J. J. Harris

The influence of spin on the Fractional Quantum Hall Effect is investigated in GaAs-GaAlAs heterojunctions in a filling factor region where both spin states of the lowest Landau level are occupied....

The dependence of the Composite Fermion effective mass on carrier density and Zeeman energy (2008)

R J Nicholas, D R Leadley, M S Daly, P Gee, J Singleton, ...

Abstract. Measurements of the temperature-dependent resistivity of high-mobility GaAs/GaAlAs heterojunctions are used to measure the effective mass of Composite Fermions (CF). The CF effective mass...

Measurements of composite Skyrmions at filling factor 1/3 (2008)

D. R. Leadley, R. J. Nicholas, D. K. Maude, A. N. Utjuzh, J. C. Portal, J. J. Harris, ...

Measurements of the fractional quantum Hall effect energy gaps at high pressures are presented that provide evidence for the existence of composite Skyrmions. Just as charged spin textures known as...

Microwave-induced forward scattering and Luttinger liquid interferences in magnetically confined quantum wires (2008)

Nogaret, Alain, Portal, J. C., Beere, H. E., Ritchie, D. A., Phillips, C.

We report on the photoresistance of a magnetic quantum wire obtained by applying a gradient of magnetic field to a two-dimensional electron gas. Electron transmission through the magnetic wire...

1 UNIVERSAL CONDUCTANCE FLUCTUATIONS AND TELEGRAPH NOISE SPECTROSCOPY TO INVESTIGATE THE MAGNETISATION OF SELF ORGANISED ErAs QUANTUM DOTS. (2007)

F. Coppinger, J. Genoe, L. B. Rigal, D. K. Maude, U. Gennser, J. C. Portal, ...

Using low temperature magnetotransport techniques we demonstrate that the electrical transport is phase coherent in a GaAs matrix containing self organising ErAs quantum dots and wires of the order...

Point contact spectroscopy of magnetic edge states (2007)

Lambert, N. J., Nogaret, A. R., Sassine, S., Portal, J. C., Beere, H. E., Ritchie, D. A.

We report on a novel ballistic electron spectrometer that images the k-space structure of open orbits confined by a magnetic field gradient. Magnetoresistance measurements were performed on a...

Magnetoresistance and resistance versus temperature dependence of a mesoporous mesophase carbon (2006)

Sassine, S., Olshanetsky, E. B., Kvon, Z. D., Mel'gunov, M. S., Mel'gunova, E. A., Portal, J. C.

In the present work the transport properties of mesoporous mesophase carbon (MMC) powder have been investigated in wide temperature and magnetic field ranges. It has been found that in the range...

Directed electron transport through a ballistic quantum dot under microwave radiation (2006)

Zhang, J. Q., Vitkalov, S., Kvon, Z. D., Portal, J. C., Wieck, A.

Rectification of microwave radiation by asymmetric ballistic dot is studied at different frequencies (1-40 GHz), temperatures, and magnetic fields. Dramatic reduction of the rectification is found in...

Coulomb blockade and the thermopower of a suspended quantum dot (2006)

Pogosov, A. G., Budantsev, M. V., Lavrov, R. A., Plotnikov, A. E., Bakarov, A. K., Toropov, A. I., ...

On the basis of the 2D electron gas in an AlGaAs/GaAs membrane separated from a wafer, a one-electron transistor is created that operates on the Coulomb blockade effect-a two-barrier structure with a...

Current-driven breakdown of the quantized Hall states of a broken-gap 2D electron-hole system (2006)

Takashina, K., Nicholas, R. J., Kardynal, B., Mason, N. J., Maude, D. K., Portal, J. C.

We report results from experimental studies on the current driven breakdown of the quantum Hall effect in an InAs/GaSb-based electron-hole system. We find that the critical currents observed in this...

Resonant tunneling of electrons between two-dimensional systems of different densities in a quantizing magnetic field (2006)

Popov, V. G., Dubrovskii, Y. V., Portal, J. C.

The results of experimental investigation of the vertical electron transport in a GaAs/Al0.3Ga0.7As/GaAs single-barrier tunneling licterostructure with a doped barrier are presented. Two-diniensional...

Directed electron transport through ballistic quantum dot under microwave radiation (2005)

Zhang, Jing-qiao, Vitkalov, Sergey, Kvon, Z. D., Portal, J. C., Wieck, A.

Rectification of microwave radiation by asymmetric, ballistic quantum dot is observed. The directed transport is studied at different frequency (1-40 GHz) temperatures (0.3K-6K)and magnetic field....

Anisotropic positive magnetoresistance of a nonplanar 2D electron gas in a parallel magnetic field (2005)

Goran, A. V., Bykov, A. A., Bakarov, A. K., Portal, J. C.

We study the transport properties of a 2D electron gas in narrow GaAs quantum wells with AlAs/GaAs superlattice barriers. It is shown that the anisotropic positive magnetoresistance observed in...

Quantum corrections to the conductivity and Hall coefficient of a 2D electron gas in a dirty AlGaAs/GaAs/AlGaAs quantum well: transition from diffusive to ballistic regime. (2005)

Renard, Vincent, Tkachenko, O. A., Kvon, Ze Don, Olshanetsky, E. B., Toropov, A. I., Portal, J.C

We report an experimental study of the quantum corrections to the longitudinal conductivity and the Hall coefficient of a low mobility, high density two-dimensional two-dimensional electron gas in a...

Quantum corrections to the conductivity and Hall coefficient of a 2D electron gas in a dirty AlGaAs/GaAs/AlGaAs quantum well: transition from diffusive to ballistic regime. (2005)

Renard, Vincent, Tkachenko, O. A., Kvon, Ze Don, Olshanetsky, E. B., Toropov, A. I., Portal, J.C

We report an experimental study of the quantum corrections to the longitudinal conductivity and the Hall coefficient of a low mobility, high density two-dimensional two-dimensional electron gas in a...

Quantum corrections to the conductivity and Hall coefficient of a 2D electron gas in a dirty AlGaAs/GaAs/AlGaAs quantum well: transition from diffusive to ballistic regime. (2005)

Renard, Vincent, Tkachenko, O. A., Kvon, Ze Don, Olshanetsky, E. B., Toropov, A. I., Portal, J.C

We report an experimental study of the quantum corrections to the longitudinal conductivity and the Hall coefficient of a low mobility, high density two-dimensional two-dimensional electron gas in a...

Quantum corrections to the conductivity and Hall coefficient of a 2D electron gas in a dirty AlGaAs/GaAs/AlGaAs quantum well: transition from diffusive to ballistic regime. (2005)

Renard, Vincent, Tkachenko, O. A., Kvon, Ze Don, Olshanetsky, E. B., Toropov, A. I., Portal, J.C

We report an experimental study of the quantum corrections to the longitudinal conductivity and the Hall coefficient of a low mobility, high density two-dimensional two-dimensional electron gas in a...

Quantum corrections to the conductivity and Hall coefficient of a 2D electron gas in a dirty AlGaAs/GaAs/AlGaAs quantum well: transition from diffusive to ballistic regime (2004)

Renard, Vincent Thomas Francois, Tkachenko, O. A., Kvon, Ze Don, Olshanetsky, E. B., Toropov, A. I., Portal, J. C

We report an experimental study of the quantum corrections to the longitudinal conductivity and the Hall coefficient of a low mobility, high density two-dimensional two-dimensional electron gas in a...

Large positive magneto-resistance in high mobility 2D electron gas : interplay of short and long range disorder (2004)

Renard, Vincent T. F, Kvon, Ze Don, Gusev, G M, Portal, J. C

We have observed a large positive quasi-classical magneto-resistance (MR) in a high mobility 2D electron gas in AlGaAs/GaAs heterostructure. The magneto-resistance is non-saturating and increases...

Large positive magneto-resistance in high mobility 2D electron gas : interplay of short and long range disorder (2004)

Renard, Vincent, Kvon, Ze Don, Gusev, G., Portal, J.C

We have observed a large positive quasi-classicalmagneto-resistance (MR) in a high mobility 2D electron gas inAlGaAs/GaAs heterostructure. The magneto-resistance isnon-saturating and increases with...

Large positive magneto-resistance in high mobility 2D electron gas : interplay of short and long range disorder (2004)

Renard, Vincent, Kvon, Ze Don, Gusev, G., Portal, J.C

We have observed a large positive quasi-classicalmagneto-resistance (MR) in a high mobility 2D electron gas inAlGaAs/GaAs heterostructure. The magneto-resistance isnon-saturating and increases with...

Large positive magneto-resistance in high mobility 2D electron gas : interplay of short and long range disorder (2004)

Renard, Vincent, Kvon, Ze Don, Gusev, G., Portal, J.C

We have observed a large positive quasi-classicalmagneto-resistance (MR) in a high mobility 2D electron gas inAlGaAs/GaAs heterostructure. The magneto-resistance isnon-saturating and increases with...

Influence of Fermi-system chirality on the temperature dependence of the Aharonov-Bohm effect (2004)

Bykov, A. A., Nomokonov, D. V., Bakarov, A. K., Goran, A. V., Estibals, O., Portal, J. C.

The Aharonov-Bohm effect in submicron rings with narrow electron channels was studied in the range of magnetic fields from 0 to 15 T and temperatures from 0.1 to 10 K. It is found that the...

Conductance of a multiterminal ballistic wire (2004)

Kvon, Z. D., Tkachenko, V. A., Plotnikov, A. E., Sablikov, V. A., Renard, V., Portal, J. C.

An experimental study of the two-, three-, and four-terminal resistance of a ballistic wire is carried out. The wire is fabricated on the basis of high-mobility 2D electron gas in an AlGaAs/GaAs...

Reduced pressure chemical vapour deposition of SiGe virtual substrates for high mobility devices (2004)

Hartmann, J. M., Bogumilowicz, Y., Holliger, P., Laugier, F., Truche, R., Rolland, G., ...

We have studied the strain state, film and surface morphology of SiGe virtual substrates grown by reduced pressure chemical vapour deposition (RP-CVD). The macroscopic strain relaxation and the Ge...

Magnetotransport of electrons in overfull quantum well (2004)

Kvon, Z. D., Tkachenko, V. A., Tkachenko, O. A., Toropov, A. I., Bakarov, A. K., Renard, V., ...

We report magnetotransport properties of electrons in a new kind of two-dimensional electron system (2DES)-a narrow single quantum well with electron density so large that the electrons splash out of...

Mesoscopic fluctuations of thermopower in a periodic antidot lattice (2004)

Budantsev, M. V., Lavrov, R. A., Pogosov, A. G., Plotnikov, A. E., Bakarov, A. K., Toropov, A. I., ...

The mesoscopic fluctuations of thermopower (MFT) were experimentally observed in an AlGaAs/GaAs heterojunction with a low-resistance (similar to0.02h/e(2)) periodic antidot lattice in the situation...

Commensurability magneto-resistance peaks in a lattice of diffusive scatterers (2004)

Renard, V., Kvon, Z. D., Estibals, O., Plotnikov, A. Y., Portal, J. C.

Commensurability peaks in new kind of two-dimensional (2D) systems with artificial scatterers-2D electron gas in the array of diffusive and thermalizing scatterers (it was AuGeNi alloy dots)-was...

Coulomb blockade in triangular lateral small-size quantum dots (2004)

Tkachenko, V. A., Kvon, Z. D., Tkachenko, O. A., Baksheev, D. G., Estibals, O., Portal, J. C.

An AlGaAs/GaAs lateral quantum dot of triangular shape with a characteristic size L < 100 nm containing less than ten electrons was studied. Single-electron oscillations of the conductance G of this...

Magnetoconductivity of a spin-polarized two-dimensional electron gas near the (111) silicon surface (2004)

Estibals, O., Kvon, Z. D., Gusev, G. M., Arnaud, G., Portal, J. C.

The magnetoresistance of a disordered and highly interacting two-dimensional electron gas (2DEG) in a silicon (I 1 1) MOSFET has been measured in the presence of a magnetic field parallel to the...

Corrections to conductivity on the metallic side of metal-insulator transition in n-Si/SiGe heterostructures (2004)

Renard, V., Ol'shanetskiĭ, E. B., Kvon, Z. D., Portal, J. C., Woods, N. J., Zhang, J., ...

We report the first observation of the metal-insulator transition (MIT) in a two-dimensional electron gas (2DEG) in a Si/SiGe heterostructure at zero field. We have performed an analysis of the...

Negative parabolic magneto-resistance induced by electron-electron interaction in two-dimensional electron gas with diffusive transport (2004)

Renard, V., Kvon, Z. D., Estibals, O., Portal, J. C., Toropov, A. I., Bakarov, A. K., ...

We experimentally study the parabolic negative magneto-resistance (NMR) in high density (N-s > 10(12) cm(-2)) and low mobility (mu < 10(3) cm(2)/V s) two-dimensional (2D) electron gas realized by...

Large positive quasi-classical magnetoresistance in high mobility 2D electron gas: Interplay of short- and long-range disorder (2004)

Kvon, Z. D., Renard, V., Gusev, G. M., Portal, J. C.

We observed a giant positive quasi-classical magnetoresistance (MR) of high mobility 2D electron gas in AlGaAs/GaAs heterostructure. The MR is non-saturating and increases with the magnetic field as...

Large positive magneto-resistance in high mobility 2D electron gas : interplay of short and long range disorder (2004)

Renard, Vincent, Kvon, Ze Don, Gusev, G., Portal, J.C

We have observed a large positive quasi-classicalmagneto-resistance (MR) in a high mobility 2D electron gas inAlGaAs/GaAs heterostructure. The magneto-resistance isnon-saturating and increases with...

Conductivity of a 2DEG in Si/SiGe heterostructure near metal- insulator transition: role of the short and long range scattering potential (2003)

Olshanetsky, E. B., Renard, V., Kvon, Z. D., Portal, J. C., Woods, N. J., Zhang, J., ...

We report the observation of a metal-insulator transition (MIT) in a two- dimensional electron gas (2DEG) in a Si/SiGe heterostructure at zero magnetic field. On going through the MIT we observe the...

Nonlinear hole transport through a submicron-size channel (2003)

Makarovsky, O., Neumann, A., Martin, A. M., Turyanska, L., Patané, A., Eaves, L., ...

We investigate hole transport through a submicron-size channel fabricated from a modulation-doped p-type GaAs/(AlGa)As single- quantum-well heterostructure. The intense electric field in the channel...

Landau levels in two and three-dimensional electron gases in a wide parabolic quantum well (2002)

Sergio,C.S., Gusev,G.M., Leite,J.R., Olshanetskii,E.B., Bykov,A.A., Moshegov,N.T., ...

Shubnikov-de Haas oscillations are measured in a wide parabolic quantum well with 6 subbands in a tilted magnetic fi eld. We find two types of oscillations. The oscillations at low magnetic field are...

Resonant Tunneling Through Single Thin Barrier Heterostructure with Spacer Layers (2002)

Khanin, Y. N., Vdovin, E. E., Dubrovskii, Y. V., Maude, D. K., Portal, J. C.

This article studied the tunneling in a single thin barrier heterostructure with spacer layers. All findings are explained in terms of resonant tunneling through triple barrier structure.

Coulomb blockade in a lateral triangular small quantum dot (2002)

Tkachenko, V. A., Kvon, Z. D., Tkachenko, O. A., Baksheev, D. G., Estibals, O., Portal, J. C.

An AlGaAs/GaAs lateral quantum dot of triangular shape with a characteristic size L < 100 nm (the smallest size for dots of this type) containing less than ten electrons was studied theoretically and...

Transport of a two-dimensional electron gas in a lattice of diffusive and thermalizing scatterers (2002)

Kvon, Z. D., Estibals, O., Plotnikov, A. Y., Portal, J. C., Toropov, A. I.

Classical and quantum transport in a new kind of two- dimensional (2D) systems with artificial scatterers-2D electron gas in an array of diffusive and thermalizing scatterers (AuGeNi alloy dots)- was...

Gated wires and interferometers based on Si/SiGe heterostructures (2002)

Estibals, O., Kvon, Z. D., Portal, J. C., Plotnikov, A. Y., Gauffier, J. L., Woods, N. J., ...

We report the fabrication and study of gated quantum wires and interferometers based on a Si/SiGe heterostructure fabricated by electron lithography and anisotropic ion etching. In the wires,...

Anomalies of the fractional quantum Hall effect in a wide ballistic wire (2002)

Kvon, Z. D., Ol'shanetskiĭ, E. B., Plotnikov, A. E., Toropov, A. I., Portal, J. C.

Magnetotransport in a ballistic wire under the conditions of integer and fractional quantization was studied experimentally. A nonlinear magnetic-field dependence of filling factor (nu) of the Landau...

Chaotic electron dynamics in antidot lattice subjected to strong in-plane magnetic field (2002)

Sotomayor Choque, N. M., Gusev, G. M., Leite, J. R., Bykov, A. A., Litvin, L. V., Moshegov, N. T., ...

The classical electron dynamics in two-dimensional antidot lattices subjected to a magnetic field with a strong in-plane component is studied numerically. The anisotropy of the Fermi contour of the...

Resistively detected nuclear magnetic resonance in the quantum Hall regime: Possible evidence for a Skyrme crystal (2002)

Desrat, W., Maude, D. K., Potemski, M., Portal, J. C., Wasilewski, Z. R., Hill, G.

Resistively detected nuclear magnetic resonance measurements have been performed on a high mobility heterostructure in the quantum Hall regime. At millikelvin temperatures the nuclear resonances are...

Landau levels in two and three-dimensional electron gases in a wide parabolic quantum well (2002)

Sergio, C. S., Gusev, G. M., Leite, J. R., Ol'shanetskiĭ, E. B., Bykov, A. A., Moshegov, N. T., ...

Shubnikov-de Haas oscillations are measured in a wide parabolic quantum well with 6 subbands in a tilted magnetic field. We find two types of oscillations. The oscillations at low magnetic field are...

Magnetotransport of a quasi-three-dimensional electron gas in the lowest Landau level (2002)

Gusev, G. M., Quivy, A. A., Lamas, T. E., Leite, J. R., Bakarov, A. K., Toropov, A. I., ...

We have observed features in the magnetoresistance of a wide parabolic quantum well in the presence of the in-plane magnetic field at field three times larger than fundamental field corresponding to...

Conductivity corrections in a strongly correlated and disordered two-dimensional electron system (2002)

Kvon, Z. D., Estibals, O., Gusev, G. M., Portal, J. C.

We have measured the resistivity rho of a dilute two- dimensional electron gas near the (111) silicon surface as a function of a temperature. Since the valley degeneracy in such structures g(v) is 6,...

Resistively detected NMR in the quantum Hall regime (2002)

Desrat, W., Maude, D. K., Potemski, M., Portal, J. C., Wasilewski, Z. R., Hill, G.

We present resistively detected nuclear magnetic resonance performed on a high mobility two-dimensional electron gas. Nuclear resonances have been observed for all three isotopes Ga-69, Ga-71 and...

Magnetic waveguiding in tilted magnetic fields (2002)

Nogaret, A., Lawton, D. N., Maude, D. K., Portal, J. C., Henini, M.

We apply tilted magnetic fields to ballistic electrons channelled by a microscopic magnetic gradient and show that the resonances in both the longitudinal and the Hall resistance are essentially a...

Magnetic field induced linear Coulomb gap in tunnelling between disordered two-dimensional electron systems (2002)

Dubrovskii, Y. V., Hill, R., Volkov, V. A., Main, P. C., Eaves, L., Popov, V. G., ...

We have investigated equilibrium tunnelling between disordered two-dimensional electron systems at temperatures below 0.3 K over a wide range of magnetic field. B. applied perpendicular to the...

Small ring interferometer on the basis of a GaAs quantum well with a high density 2D electron gas (2002)

Bykov, A. A., Estibals, O., Marchishin, I. V., Litvin, L. V., Bakarov, A. K., Toropov, A. I., ...

Magneto-transport properties of small ring interferometers with narrow electronic channels made on the basis of a 2D electron gas in a GaAs quantum well with AlAs/GaAs superlattice barriers are...

Single-electron conductance oscillations of small open quantum dot (2002)

Kvon, Z. D., Estibals, O., Plotnikov, A. Y., Portal, J. C., Toropov, A. I., Gauffier, J. L.

We study the conductance of three-lead small open quantum dots fabricated on the basis of a high mobility two-dimensional (2D) electron gas in an AlGaAs/GaAs heterostructure. Large conductance...

Probing the electronic properties of disordered two-dimensional systems by means of resonant tunnelling (2001)

Dubrovskii, Y. V., Vdovin, E. E., Patané, A., Brounkov, P. N., Larkin, I. A., Eaves, L., ...

We investigate resonant tunnelling in GaAs/(AlGa)As double- barrier resonant-tunnelling diodes in which a single layer of InAs self-assembled quantum dots is embedded in the centre of the GaAs...

Negative magnetoresistance due to ballistic weak localization in a dense hexagonal lattice of antidots (2001)

Pouydebasque, A., Pogosov, A. G., Budantsev, M. V., Plotnikov, A. E., Toropov, A. I., Maude, D. K., ...

An experimental analysis of the negative magnetoresistance due to weak localization in a dense hexagonal lattice of antidots created from a two-dimensional electron gas formed at an AlGaAs/GaAs...

Metal-Insulator oscillations in a Two-dimensional Electron-Hole system (1999)

Nicholas, R. J., Takashina, K., Lakrimi, M., Kardynal, B., Khym, S., Mason, N. J., ...

The electrical transport properties of a bipolar InAs/GaSb system have been studied in magnetic field. The resistivity oscillates between insulating and metallic behaviour while the quantum Hall...

Quantum hall effect in a wide parabolic quantum well (1999)

Gusev,G.M., Leite,J.R., Olshanetskii,E.B., Maude,D.K., Cassé,M., Portal,J.C., ...

We investigate the activated conductivity for Landau levels at lling factors v =1,2 in a parabolic Al xGa1-x As well down to 30 mK. We obtain a very small activation energy ~ 0.02 meV, which is...

Proximity effects and Andreev reflection in mesoscopic SNS junction with perfect NS interfaces (1999)

Kvon, Z. D., Baturina, T. I., Donaton, R. A., Baklanov, M. R., Maex, K., Olshanetsky, E. B., ...

Low temperature transport measurements on superconducting film - normal metal wire - superconducting film (SNS) junctions fabricated on the basis of 6 nm thick superconducting polycrystalline PtSi...

Temperature dependence of the magnetoresistance minima in n-channel Si/Si1-xGex modulation-doped quantum well structures (1999)

Shin, D. H., Becker, C. E., Harris, J. J., Fernandez, J. M., Woods, N. J., Thornton, T. J., ...

Shubnikov-de Haas (SdH) measurements between 0.04 and 4.2K have been performed on two modulation-doped n-type Si/Si0.7Ge0.3 heterostructures, and the temperature dependence of the resistivity minima...

Searches for Skyrmions in the Limit of Zero g-Factor (1998)

Leadley, D. R., Nicholas, R. J., Maude, D. K., Utjuzh, A. N., Portal, J. C., Harris, J. J., ...

Energy gaps have been measured for the ferromagnetic quantum Hall effect states at v=1 and 3 in GaAs/GaAlAs heterojunctions as a function of Zeeman energy, which is reduced to zero by applying...

2D Lattice of coupled Sinai billiards: metal or insulator at g (1998)

Budantsev, M. V., Kvon, Z. D., Pogosov, A. G., Gusev, G. M., Portal, J. C., Maude, D. K., ...

We investigate the transport in a two-dimensional (2D) lattice of coupled Sinai billiards fabricated on the basis of a high-mobility 2D electron gas in GaAs/AlGaAs heterojunction. For the states with...

Skyrmions and composite fermions in the limit of vanishing Zeeman energy (1998)

R J Nicholas, D R Leadley, D K Maude, J C Portal, J J Harris, C T Foxon

Abstract. We describe the properties of a strongly interacting two-dimensional (2D) electron gas in high magnetic fields whose properties can be described in terms of the formation of composite...

Searches for skyrmions in the limit of zero g-factor (1998)

D R Leadley, R J Nicholas, D K Maude, A N Utjuzh, J C Portal, J J Harris, ...

Abstract. Energy gaps have been measured for the ferromagnetic quantum Hall effect states at ν = 1 and 3 in GaAs/Ga0.7Al0.3As heterojunctions as a function of Zeeman energy, which is reduced to zero...

Interaction effects at the magnetic-field induced metal-insulator transition in Si/SiGe superlattices (1997)

Brunthaler, G., Dietl, T., Prinz, A., Sawicki, M., Jaroszynski, J., Glod, P., ...

A metal-insulator transition was induced by in-plane magnetic fields up to 27 T in homogeneously Sb-doped Si/SiGe superlattice structures. The localisation is not observed for perpendicular magnetic...

Edge Channel Dominated Magnetotransport in PbTe Wide Parabolic Quantum Wells (1997)

Oswald, J., Span, G., Homer, A., Heigl, G., Ganitzer, P., Maude, D. K., ...

In PbTe wide parabolic quantum wells (WPQW) a plateau-like structure is observed in the Hall resistance, which corresponds to the Shubnikov-de Haas oscillations in the same manner as known from the...

Phasecoherent Transport in PbTe Wide Parabolic Quantum Wells (1997)

Oswald, J., Span, G., Homer, A., Heigl, G., Ganitzer, P., Maude, D. K., ...

Conductance fluctuations have been observed in macroscopic, quasi 3D PbTe wide quantum wells. A significant increase of the correlation field occurs in a temperature range from 40 mK to 1.2K. At the...

Magnetotransport in wide parabolic PbTe quantum wells (1997)

Oswald, J., Heigl, G., Pippan, M., Span, G., Stellberger, T., Maude, D. K., ...

The 3D- and 2D- behaviour of wide parabolic PbTe single quantum wells, which consist of PbTe p-n-p-structures, are studied theoretically and experimentally. A simple model combines the 2D- subband...

Conductance Fluctuations in PbTe Wide Parabolic Quantum Wells (1997)

Oswald, J., Heigl, G., Span, G., Homer, A., Ganitzer, P., Maude, D. K., ...

We report on conductance fluctuations which are observed in local and non-local magnetotransport experiments. Although the Hall bar samples are of macroscopic size, the amplitude of the fluctuations...

Quenching of the Quantum Hall Effect in PbTe Wide Parabolic Quantum Wells (1997)

Oswald, J., Heigl, G., Span, G., Homer, A., Ganitzer, P., Maude, D. K., ...

We show that for the case of a many valley host semiconductor an edge channel (EC) related non-local behaviour can persist also in the 3D-regime where the quantum Hall effect (QHE) is already...

Non Local Transport in PbTe Wide Parabolic Quantum Wells (1997)

Oswald, J., Heigl, G., Span, G., Homer, A., Ganitzer, P., Maude, D. K., ...

The results of non-local experiments in different contact configurations are discussed in terms of a non-local behaviour of the contact arms. It is shown that the observed reproducible fluctuations...

Anomalous magnetotransport in wide quantum wells (1997)

Oswald, J., Span, G., Homer, A., Heigl, G., Ganitzer, P., Maude, D. K., ...

We present magneto transport experiments of quasi 3D PbTe wide quantum wells. A plateau-like structure in the Hall resistance is observed, which corresponds to the Shubnikov de Haas oscillations in...

Fractional Quantum Hall Effect Measurements at Zero g-Factor (1997)

Leadley, D. R., Nicholas, R. J., Maude, D. K., Utjuzh, A. N., Portal, J. C., Harris, J. J., ...

Fractional quantum Hall effect energy gaps have been measured in GaAs/GaAlAs heterojunctions as a function of Zeeman energy, which is varied by applying hydrostatic pressure up to 20 kbar. The gap at...

Etudes sous champ magnétique de l'effet tunnel résonnant et non résonnant dans les structures à double barrière n-(AlGa)As/GaAs (1989)

Celeste, A., Portal, J.C., Eaves, L., Alves, E.S., Foster, T.J., Leadbeater, M. L., ...

Nous avons étudié les propriétés électroniques d'une série de structures à double barrière, dont la largeur du puits varie de 5 à 6 nm. La bistabilité observée couramment dans les...

Propriétés électroniques quasi-bidimensionnelles de couches épitaxiales de GaAs à dopage δ (1989)

Lavielle, D., Portal, J.C., Stohr, M., Najda, S.P., Briggs, A., Gillmann, G., ...

Nous présentons ici une étude des propriétés de transport électronique de structures à dopage planaire Si dans GaAs. Nous utilisons des forts champs magnétiques continus et des basses...

Etudes sous champ magnétique de l'effet tunnel résonnant et non résonnant dans les structures à double barrière n-(AlGa)As/GaAs (1989)

Celeste, A., Portal, J.C., Eaves, L., Alves, E.S., Foster, T.J., Leadbeater, M. L., ...

Nous avons étudié les propriétés électroniques d'une série de structures à double barrière, dont la largeur du puits varie de 5 à 6 nm. La bistabilité observée couramment dans les...

Propriétés électroniques quasi-bidimensionnelles de couches épitaxiales de GaAs à dopage δ (1989)

Lavielle, D., Portal, J.C., Stohr, M., Najda, S.P., Briggs, A., Gillmann, G., ...

Nous présentons ici une étude des propriétés de transport électronique de structures à dopage planaire Si dans GaAs. Nous utilisons des forts champs magnétiques continus et des basses...

Etudes sous champ magnétique de l'effet tunnel résonnant et non résonnant dans les structures à double barrière n-(AlGa)As/GaAs (1989)

Celeste, A., Portal, J.C., Eaves, L., Alves, E.S., Foster, T.J., Leadbeater, M. L., ...

Nous avons étudié les propriétés électroniques d'une série de structures à double barrière, dont la largeur du puits varie de 5 à 6 nm. La bistabilité observée couramment dans les...

Propriétés électroniques quasi-bidimensionnelles de couches épitaxiales de GaAs à dopage δ (1989)

Lavielle, D., Portal, J.C., Stohr, M., Najda, S.P., Briggs, A., Gillmann, G., ...

Nous présentons ici une étude des propriétés de transport électronique de structures à dopage planaire Si dans GaAs. Nous utilisons des forts champs magnétiques continus et des basses...