Lavagnini, M., Baldini, M., Sacchetti, A., Di Castro, D., Delley, B., Monnier, R., ...
We report on a Raman scattering investigation of the charge-density-wave (CDW), quasi two-dimensional rare-earth tri-tellurides $R$Te$_3$ ($R$= La, Ce, Pr, Nd, Sm, Gd and Dy) at ambient pressure, and...
Lasing via Ground-State Transitions in V-Groove Quantum Wire Lasers (2008)
Sirigu, L., Degiorgi, L., Oberli, D.Y., Rudra, A., Kapon, E.
Excitonic Lasing in Semiconductor Quantum Wires (2008)
Sirigu, L., Oberli, D.Y., Degiorgi, L., Rudra, A., Kapon, E.
Pfuner, F., Degiorgi, L., Shin, K. Y., Fisher, I. R.
We investigate the rare-earth polychalcogenide $R_2$Te$_5$ ($R$=Nd, Sm and Gd) charge-density-wave (CDW) compounds by optical methods. From the absorption spectrum we extract the excitation energy of...
Pressure dependence of the optical properties of the charge-density-wave compound LaTe$_2$ (2007)
Lavagnini, M., Sacchetti, A., Degiorgi, L., Arcangeletti, E., Baldassarre, L., Postorino, P., ...
We report the pressure dependence of the optical response of LaTe$_2$, which is deep in the charge-density-wave (CDW) ground state even at 300 K. The reflectivity spectrum is collected in the...
DC and optical conductivity of icosahedral quasicrystal Al70Mn9Pd21 (2007)
Chernikov, MA, Degiorgi, L, Bernasconi, A, Beeli, C, Ott, HR
Optical properties of the Ce and La di-telluride charge density wave compounds (2007)
Lavagnini, M., Sacchetti, A., Degiorgi, L., Shin, K. Y., Fisher, I. R.
The La and Ce di-tellurides LaTe$_2$ and CeTe$_2$ are deep in the charge-density-wave (CDW) ground state even at 300 K. We have collected their electrodynamic response over a broad spectral range...
Mitrovic, S., Perfetti, L., Sondergaard, C., Margaritondo, G., Grioni, M., Barisic, N., ...
High-resolution angle-resolved photoemission (ARPES) displays quasi-one dimensional (1D) electronic states in the insulating molybdenum red bronze K0.33MoO3, in good qualitative agreement with band...
Zwick, F., Grioni, M., Margaritondo, G., Vescoli, V., Degiorgi, L., Alavi, B., ...
We performed optical and photoemission experiments on the Bechgaard salt (TMTSF)(2)ReO4, a quasi-one-dimensional (1D) organic conductor that undergoes a metal-insulator (Peierls) transition at T-c...
Perfetti, L., Berger, H., Reginelli, A., Degiorgi, L., Hochst, H., Voit, J., ...
Angle-resolved photoemission (ARPES) on the quasi-one-dimensional conductor (TaSe4)(2)I shows a hidden Fermi-surface crossing in its metallic state and the opening of a Peierls gap at low...
Perfetti, L., Mitrovic, S., Margaritondo, G., Grioni, M., Forro, L., Degiorgi, L., ...
High-resolution angle-resolved photoemission spectroscopy (ARPES) on the quasi-one-dimensional Peierls system K0.3MoO3 reveals a "hidden" open Fermi surface and band features displaying the symmetry...
Pressure dependence of the charge-density-wave gap in rare-earth tri-tellurides (2006)
Sacchetti, A., Arcangeletti, E., Perucchi, A., Baldassarre, L., Postorino, P., Lupi, S., ...
We investigate the pressure dependence of the optical properties of CeTe$_3$, which exhibits an incommensurate charge-density-wave (CDW) state already at 300 K. Our data are collected in the...
Sacchetti, A., Degiorgi, L., Giamarchi, T., Ru, N., Fisher, I. R.
We report on the first optical measurements of the rare-earth tri-telluride charge-density-wave systems. Our data, collected over an extremely broad spectral range, allow us to observe both the Drude...
Optical evidence for a magnetically driven structural transition in the spin web $Cu_3TeO_6$ (2005)
Caimi, G., Degiorgi, L., Berger, H., Forro, L.
$Cu_3TeO_6$ is a modest frustrated $S=1/2$ spin system, which undergoes an anti-ferromagnetic transition at $T_N\sim61$ $K$. The anti-ferromagnetic spin alignment in $Cu_3TeO_6$ below $T_N$ is...
Optical investigation of the metal-insulator transition in $FeSb_2$ (2005)
Perucchi, A., Degiorgi, L., Hu, R., Petrovic, C., Mitrovi{ć}, V.
We present a comprehensive optical study of the narrow gap $FeSb_2$ semiconductor. From the optical reflectivity, measured from the far infrared up to the ultraviolet spectral range, we extract the...
Magneto-optical evidence of double exchange in a percolating lattice (2005)
Caimi, G., Perucchi, A., Degiorgi, L., Ott, H. R., Pereira, V. M., Castro-Neto, A. H., ...
Substituting $Eu$ by $Ca$ in ferromagnetic $EuB_6$ leads to a percolation limited magnetic ordering. We present and discuss magneto-optical data of the $Eu_{1-x}Ca_{x}B_6$ series, based on...
Infrared signature of the charge-density-wave gap in $ZrTe_3$ (2005)
Perucchi, A., Degiorgi, L., Berger, H.
The chain-like $ZrTe_3$ compound undergoes a charge-density-wave (CDW) transition at $T_{CDW}=63$ $K$, most strongly affecting the conductivity perpendicular to the chains. We measure the temperature...
Süllow, S., Maksimov, I., Otop, A., Litterst, F. J., Perucchi, A., Degiorgi, L., ...
We present a detailed study of the electronic transport properties on a single crystalline specimen of the moderately disordered heavy fermion system URh$_2$Ge$_2$. For this material, we find glassy...
Analysis of the phonon spectrum in the titanium oxyhalide TiOBr (2004)
Caimi, G., Degiorgi, L., Lemmens, P., Chou, F. C.
We present the electrodynamic response of TiOBr, which undergoes a transition to a spin-singlet ground state for temperatures below T$_{C1}=28$ K. The temperature evolution of the phonon anomalies...
Optical evidence for the proximity to a spin-density-wave metallic state in Na$_{0.7}$CoO$_2$ (2004)
Caimi, G., Degiorgi, L., Berger, H., Barisic, N., Forro, L., Bussy, F.
We present the optical properties of \na single crystals, measured over a broad spectral range as a function of temperature ($T$). The capability to cover the energy range from the far-infrared up to...
Infrared optical properties of the spin-1/2 quantum magnet TiOCl (2004)
Caimi, G., Degiorgi, L., Kovaleva, N. N., Lemmens, P., Chou, F. C.
We report results on the electrodynamic response of TiOCl, a low-dimensional spin-1/2 quantum magnet that shows a spin gap formation for T
Giant phonon softening in the pseudogap phase of the quantum spin system TiOCl (2004)
Lemmens, P., Caimi, G., Degiorgi, L., Kovaleva, N. N., Seidel, A., ...
Optical investigation of the charge-density-wave phase transitions in $NbSe_{3}$ (2003)
Perucchi, A., Degiorgi, L., Thorne, R. E.
We have measured the optical reflectivity $R(\omega)$ of the quasi one-dimensional conductor $NbSe_{3}$ from the far infrared up to the ultraviolet between 10 and 300 $K$ using light polarized along...
Infrared optical properties of the spin-1/2 quantum magnet $TiOCl$ (2003)
Caimi, G., Degiorgi, L., Kovaleva, N. N., Lemmens, P., Chou, F. C.
We report results on the electrodynamic response of $TiOCl$, a low-dimensional spin-1/2 quantum magnet that shows a spin gap formation for T$
Giant phonon anomalies in the pseudo-gap phase of TiOCl (2003)
Lemmens, P., Choi, K. Y., Caimi, G., Degiorgi, L., Kovaleva, N. N., Seidel, A., ...
We report infrared and Raman spectroscopy results of the spin-1/2 quantum magnet TiOCl. Giant anomalies are found in the temperature dependence of the phonon spectrum, which hint to unusual coupling...
Magneto-optical Kerr effect in $Eu_{1-x}Ca_{x}B_{6}$ (2003)
Caimi, G., Broderick, S., Ott, H. R., Degiorgi, L., Bianchi, A. D., Fisk, Z.
We have measured the magneto-optical Kerr rotation of ferromagnetic $Eu_{1-x}Ca_{x}B_{6}$ with x=0.2 and 0.4, as well as of $YbB_{6}$ serving as the non-magnetic reference material. As previously for...
Optical evidence for a spin-filter effect in the charge transport of $Eu_{0.6}Ca_{0.4}B_{6}$ (2003)
Perucchi, A., Caimi, G., Ott, H. R., Degiorgi, L., Bianchi, A. D., Fisk, Z.
We have measured the optical reflectivity $R(\omega)$ of $Eu_{0.6}Ca_{0.4}B_{6}$ as a function of temperature between 1.5 and 300 $K$ and in external magnetic fields up to 7 $T$. The slope at the...
MgB2 single crystals: high pressure growth and anisotropic properties (2002)
Karpinski, J., Angst, M., Jun, J., Kazakov, S. M., Puzniak, R., Wisniewski, A., ...
Single crystals of MgB2 with a size up to 1.5x0.9x0.2 mm3 have been grown with a high pressure cubic anvil technique. The crystal growth process is very peculiar and involves an intermediate nitride,...
Magneto-optical reflectivity of superconducting MgB2 single crystals (2002)
Perucchi, A., Degiorgi, L., Jun, J., Angst, M., Karpinski, J.
We present magneto-optical reflectivity results in the basal-plane of the hexagonal $MgB_2$. The data were collected on a mosaic of $MgB_2$ single crystals with $T_{c}=38 ~K$ from the ultraviolet...
Dordevic, S. V., Basov, D. N., Slebarski, A., Maple, M. B., Degiorgi, L.
We report on the electrodynamics of a Heusler alloy Fe2TiSn probed over four decades in energy: from the far infrared to the ultraviolet. Our results do not support the suggestion of Kondo-lattice...
Excitonic lasing in semiconductor quantum wires (1999)
Sirigu, L., Oberli, D. Y., Degiorgi, L., Rudra, A., Kapon, E.
Direct experimental evidences for excitonic lasing is obtained in optically pumped V-groove quantum wire structures. We demonstrate that laser emission at a temperature of 10 K arises from a...
Stripe Conductivity in La(1.775)Sr(0.225)NiO(4) (1999)
Pashkevich, Yu. G., Blinkin, V. A., Gnezdilov, V. P., Tsapenko, V. V., Eremenko, V. V., Lemmens, P., ...
We report Raman light-scattering and optical conductivity measurements on a single crystal of La(1.775)Sr(0.225)NiO(4) which exhibits incommensurate charge-stripe order. The extra phonon peaks...
Optical Properties of MFe_4P_12 filled skutterudites (1999)
Dordevic, S. V., Dilley, N. R., Bauer, E. D., Basov, D. N., Maple, M. B., Degiorgi, L.
Infrared reflectance spectroscopy measurements were made on four members of the MFe_4P_12 family of filled skutterudites, with M=La, Th, Ce and U. In progressing from M=La to U the system undergoes a...
Schwartz, A., Dressel, M., Gruner, G., Vescoli, V., Degiorgi, L., Giamarchi, T.
We have measured the electrodynamic response in the metallic state of three highly anisotropic conductors, (TMTSF)_2 X, where X=PF_6, AsF_6, or ClO_4, and TMTSF is the organic molecule...
THE ZERO-GAP Ce3Au3Sb4-x SYSTEM: A TRANSPORT,THERODYNAMIC AND OPTICAL STUDY (1998)
Broderick,S., Vescoli,V., Buschinger,B., Guth,W., Trovarelli,O., Weiden,M., ...
THE OPTICAL PROPERTIES OF RuSi: KONDO INSULATOR OR CONVENTIONAL SEMICONDUCTOR? (1998)
Vescoli,V., Degiorgi,L., Buschinger,B., Guth,W., Geibel,C., Steglich,F.
THE ZERO-GAP Ce3Au3Sb4-x SYSTEM: A TRANSPORT,THERODYNAMIC AND OPTICAL STUDY (1998)
Broderick, S., Vescoli, V., Buschinger, B., Guth, W., Trovarelli, O., Weiden, M., ...
THE OPTICAL PROPERTIES OF RuSi: KONDO INSULATOR OR CONVENTIONAL SEMICONDUCTOR? (1998)
Vescoli, V., Degiorgi, L., Buschinger, B., Guth, W., Geibel, C., Steglich, F.
RuSi: metal-semiconductor transition by change of structure (1997)
Buschinger,B., Guth,W., Weiden,M., Geibel,C., Steglich,F., Vescoli,V., ...
RuSi: metal-semiconductor transition by change of structure (1997)
Buschinger, B., Guth, W., Weiden, M., Geibel, C., Steglich, F., Vescoli, V., ...
Phason excitations in the SDW state of (TMTSF)2PF6 (1993)
Donovan, S., Kim, Y., Degiorgi, L., Grüner, G.
We have measured the frequency dependent conductivity at various temperatures below the SDW transition in (TMTSF)2PF6. We find two distinct resonances which we ascribe to internal deformations and...
Fluctuation effects in the electrodynamic response of charge density wave condensates (1993)
We report on the temperature dependence of the electrodynamic response of the CDW model compound K0.3MoO3 and its alloys. We found clear evidence of a pseudogap excitation and of the formation of a...
Fluctuation effects in the electrodynamic response of charge density wave condensates (1993)
We report on the temperature dependence of the electrodynamic response of the CDW model compound K0.3MoO3 and its alloys. We found clear evidence of a pseudogap excitation and of the formation of a...
Phason excitations in the SDW state of (TMTSF)2PF6 (1993)
Donovan, S., Kim, Y., Degiorgi, L., Grüner, G.
We have measured the frequency dependent conductivity at various temperatures below the SDW transition in (TMTSF)2PF6. We find two distinct resonances which we ascribe to internal deformations and...
Fluctuation effects in the electrodynamic response of charge density wave condensates (1993)
We report on the temperature dependence of the electrodynamic response of the CDW model compound K0.3MoO3 and its alloys. We found clear evidence of a pseudogap excitation and of the formation of a...
Phason excitations in the SDW state of (TMTSF)2PF6 (1993)
Donovan, S., Kim, Y., Degiorgi, L., Grüner, G.
We have measured the frequency dependent conductivity at various temperatures below the SDW transition in (TMTSF)2PF6. We find two distinct resonances which we ascribe to internal deformations and...
Fluctuating conductivity above the charge density wave transition in K0.3MoO3 (1992)
We have measured the optical conductivity of K0.3MoO3 both above and below the charge density wave transition. We find clear evidence for a collective mode contribution to the optical conductivity...
Fluctuating conductivity above the charge density wave transition in K0.3MoO3 (1992)
We have measured the optical conductivity of K0.3MoO3 both above and below the charge density wave transition. We find clear evidence for a collective mode contribution to the optical conductivity...
Fluctuating conductivity above the charge density wave transition in K0.3MoO3 (1992)
We have measured the optical conductivity of K0.3MoO3 both above and below the charge density wave transition. We find clear evidence for a collective mode contribution to the optical conductivity...
3d PHOTOEMISSION FROM MIXED VALENT YbH2.6 (1987)
BÜchler, S., Schlapbach, L., Monnier, R., Degiorgi, L.
In certain compounds Yb has an unstable 4f13-4f14 ground state configuration, comparable to the unstable 4f0-4f1 configuration of Ce, for which numerous studies of the 3d core levels converged to a...
Yb 3d CORE-LEVEL PHOTOEMISSION OF YbN, YbP AND YbAs (1987)
Greber, T., Degiorgi, L., Monnier, R., Schlapbach, L., Hulliger, F., Kaldis, E.
We present an experimental and theoretical study of the 3d core level spectra along the pnicitides YbN, YbP and YbAs and determine the degree of valence mixing as a function of anion...
3d PHOTOEMISSION FROM MIXED VALENT YbH2.6 (1987)
BÜchler, S., Schlapbach, L., Monnier, R., Degiorgi, L.
In certain compounds Yb has an unstable 4f13-4f14 ground state configuration, comparable to the unstable 4f0-4f1 configuration of Ce, for which numerous studies of the 3d core levels converged to a...
Yb 3d CORE-LEVEL PHOTOEMISSION OF YbN, YbP AND YbAs (1987)
Greber, T., Degiorgi, L., Monnier, R., Schlapbach, L., Hulliger, F., Kaldis, E.
We present an experimental and theoretical study of the 3d core level spectra along the pnicitides YbN, YbP and YbAs and determine the degree of valence mixing as a function of anion...
3d PHOTOEMISSION FROM MIXED VALENT YbH2.6 (1987)
BÜchler, S., Schlapbach, L., Monnier, R., Degiorgi, L.
In certain compounds Yb has an unstable 4f13-4f14 ground state configuration, comparable to the unstable 4f0-4f1 configuration of Ce, for which numerous studies of the 3d core levels converged to a...
Yb 3d CORE-LEVEL PHOTOEMISSION OF YbN, YbP AND YbAs (1987)
Greber, T., Degiorgi, L., Monnier, R., Schlapbach, L., Hulliger, F., Kaldis, E.
We present an experimental and theoretical study of the 3d core level spectra along the pnicitides YbN, YbP and YbAs and determine the degree of valence mixing as a function of anion...
Unresponsiveness to Mlsa induced in newborn Mlsb mice by maternal preimmunization.
Matossian-Rogers, A, DeGiorgi, L, DeGiori, L
Female BALB/c (H-2d, Mlsb) mice alloimmunized prior to and during syngeneic pregnancy with DBA/2 (H-2d, Mlsa) splenocytes gave rise to offspring with severely reduced responsiveness in adult life to...
Reduction of graft-versus-host disease in neonatal F1 hybrid mice.
DeGiorgi, L, Habeshaw, J A, Povey, S, Matossian-Rogers, A
Pre-immunization of BALB/c (H-2d) mothers with C57BL/10 (H-2b) or CBA/H (H-2k) spleen cells partially protected the F1 hybrid offspring of (BALB/c x C57BL/10) or (BALB/c x CBA/H) matings from...