Evtushinsky, D. V., Inosov, D. S., Urbanik, G., Zabolotnyy, V. B., Schuster, R., Sass, P., ...
Density waves are inherent to the phase diagrams of materials that exhibit unusual, and sometimes extraordinarily useful properties, such as superconductivity and colossal magnetoresistance. While...
Zabolotnyy, V. B., Kordyuk, A. A., Inosov, D. S., Evtushinsky, D. V., Schuster, R., Buechner, B., ...
We present a photoemission study of La$_{0.8-x}$Eu$_{0.2}$Sr$_x$CuO$_{4}$ with doping level $x$=1/8, where the charge carriers are expected to order forming static stripes. Though the local probes in...
Inosov, D. S., Evtushinsky, D. V., Koitzsch, A., Zabolotnyy, V. B., Borisenko, S. V., Kordyuk, A. A., ...
We present first-time measurements of the Fermi surface and low-energy electronic structure of intermetallic compounds Gd2PdSi3 and Tb2PdSi3 by means of angle-resolved photoelectron spectroscopy...
Unexpected Fermi surface topology in the new pnictide superconductor (2008)
Zabolotnyy, V. B., Inosov, D. S., Evtushinsky, D. V., Koitzsch, A., Kordyuk, A. A., Park, J. T., ...
Discovery of superconductivity in pnictides filled in the gap between the critical transition temperatures of conventional and unconventional superconductors [1-10]. According to first angle-resolved...
Evidence for antiferromagnetic correlations in superconducting LaFeAsO$_{1-x}$F$_x$ (2008)
Klingeler, R., Leps, N., Hellmann, I., Popa, A., Hess, C., Kondrat, A., ...
We have studied the interplay of magnetism and superconductivity in LaFeAsO$_{1-x}$F$_x$ with $0\leq x \leq 0.125$. For low doping with $x\leq 0.04$, our data confirm a moderate suppression of both...
Magnetic Ordering and Negative Thermal Expansion in PrFeAsO (2008)
Kimber, S. A. J., Argyriou, D. N., Yokaichiya, F., Habicht, K., Gerischer, S., Hansen, T., ...
We report the structure and magnetism of PrOFeAs, one of the parent phases of the newly discovered Fe-As superconductors, as measured by neutron powder diffraction. In common with other REOFeAs...
Inosov, D. S., Evtushinsky, D. V., Zabolotnyy, V. B., Kordyuk, A. A., Buechner, B., Follath, R., ...
Temperature evolution of the 2H-TaSe2 Fermi surface (FS) is studied by high-resolution angle-resolved photoemission spectroscopy (ARPES). High-accuracy determination of the FS geometry was possible...
Bajpai, A., Klingeler, R., Wizent, N., Nigam, A. K., Cheong, S-W., Buechner, B.
We present low field thermoremanent magnetization (TRM) measurements in granular CrO2 and composites of ferromagnetic (FM) CrO2 and antiferromagnetic (AFM) Cr2O3. TRM in these samples is seen to...
Electronic phase diagram of the LaO1-xFxFeAs superconductor (2008)
Luetkens, H., Kraken, M., Litterst, F. J., Dellmann, T., Klingeler, R., ...
Recently high-temperature superconductivity has been discovered in ironpnictides providing a new class of unconventional superconductors4,5,6. Similar as in the unconventional superconductors...
Kroll, T., Bonhommeau, S., Kachel, T., Duerr, H. A., Werner, J., Behr, G., ...
We investigated the recently found superconductor LaO_{1-x}F_xFeAs by X-ray absorption spectroscopy (XAS). From a comparison of the O K-edge with LDA calculations we find good agreement and are able...
Fuchs, G., Kozlova, N., Behr, G., Koehler, A., Werner, J., ...
We report upper critical field B_c2(T) data for disordered (As deficient) LaO_0.9F_0.1FeAs_(1-delta) in a wide temperature and field range up to 47 T. Due to the large initial slope of dBc2/dT about...
Ivek, T., Vuletic, T., Korin-Hamzic, B., Milat, O., Tomic, S., Gorshunov, B., ...
The charge transport in the copper-oxygen chain/ladder layers of (La,Y)y(Sr,Ca)14-yCu24O41 is investigated along two crystallographic directions in the temperature range from 50 K to 700 K and for...
Fermi surface nesting in several transition metal dichalcogenides (2008)
Inosov, D. S., Zabolotnyy, V. B., Evtushinsky, D. V., Kordyuk, A. A., Buechner, B., Follath, R., ...
By means of high-resolution angle resolved photoelectron spectroscopy (ARPES) we have studied the fermiology of 2H transition metal dichalcogenide polytypes TaSe2, NbSe2, and Cu0.2NbS2. The...
$^{75}$As NMR studies of superconducting LaO$_{0.9}$F$_{0.1}$FeAs (2008)
Paar, D., Lang, G., Curro, N. J., Behr, G., Werner, J., ...
We have performed 75As Nuclear Magnetic Resonance (NMR) measurements on aligned powders of the new LaO0.9F0.1FeAs superconductor. In the normal state, we find a strong temperature dependence of the...
Grobosch, M., Koepernik, K., Behr, G., Koehler, A., Werner, J., ...
We have studied the reflectance of the recently discovered superconductor LaO0.9F0.1FeAs in a wide energy range from the far infrared to the visible regime. We report on the observation of infrared...
Commensurate Spin Density Wave in LaOFeAs: A Local Probe Study (2008)
Luetkens, H., Klingeler, R., Hess, C., Litterst, F. J., Kraken, M., ...
We present a detailed study on the magnetic order in the undoped mother compound LaOFeAs of the recently discovered Fe-based superconductor LaO$_{1-x}$F$_x$FeAs. In particular, we present local probe...
Pseudogap-driven Hall effect sign reversal (2008)
Evtushinsky, D. V., Borisenko, S. V., Kordyuk, A. A., Zabolotnyy, V. B., Inosov, D. S., Buechner, B., ...
We present a calculation of the Hall coefficient in 2H-TaSe2 and 2H-Cu0.2NbS2 relied on the photoemission data and compare the results to transport observations. The approach, based on the solution...
Excitation energy map of the high-energy dispersion anomalies in cuprates (2008)
Inosov, D. S., Schuster, R., Kordyuk, A. A., Fink, J., Borisenko, S. V., Zabolotnyy, V. B., ...
The anomalous high-energy dispersion of the conductance band in the high-Tc superconductor Pb-Bi2212 has been extensively mapped by angle-resolved photoemission (ARPES) as a function of excitation...
Spin Frustration and Magnetic Exchange in Cobalt Aluminum Oxide Spinels (2007)
Tristan, N., Zestrea, V., Behr, G., Klingeler, R., Buechner, B., ...
We report on x-ray diffraction, magnetic susceptibility, electron- spin resonance and heat- capacity studies of Co[Al_1-xCo_x]_2O_4 for Co concentrations 0
Momentum and excitation energy dependence of the "waterfalls" in cuprates (2007)
Inosov, D. S., Fink, J., Kordyuk, A. A., Borisenko, S. V., Zabolotnyy, V. B., Schuster, R., ...
Using high-resolution angle-resolved photoemission spectroscopy we have studied the momentum and photon energy dependence of the anomalous high-energy dispersion, termed "waterfalls", between the...
Electron Spin Dynamics of the Superconductor CaC6 probed by ESR (2007)
Muranyi, F., Urbanik, G., Kataev, V., Buechner, B.
Conduction Electron Spin Resonance (CESR) was measured on a thick slab of CaC6 in the normal and superconducting state. A surprising increase of the CESR intensity below Tc can not be explained by...
Pseudogap and charge density waves in two dimensions (2007)
Borisenko, S. V., Kordyuk, A. A., Yaresko, A. N., Zabolotnyy, V. B., Inosov, D. S., Schuster, R., ...
An interaction between electrons and lattice vibrations (phonons) results in two fundamental quantum phenomena in solids: in three dimensions it can turn a metal into a superconductor whereas in one...
Geck, J., Borisenko, S. V., Berger, H., Eschrig, H., Fink, J., Knupfer, M., ...
We report an angular resolved photoemission study of Na0.73CoO2 where it is found that the renormalization of the quasiparticle (QP) dispersion changes dramatically upon a rotation from GM to GK. The...
"Waterfalls" phenomenon in superconducting cuprates (2007)
Inosov, D. S., Kordyuk, A. A., Borisenko, S. V., Zabolotnyy, V. B., Fink, J., Knupfer, M., ...
We show that the "waterfalls", as reported in recent ARPES studies on HTSC, can neither be described as a part of a self-consistent quasiparticle spectrum nor represent a new physical phenomena,...
"Waterfalls" in cuprates (2007)
Kordyuk, A. A., Borisenko, S. V., Inosov, D., Zabolotnyy, V. B., Fink, J., Buechner, B., ...
New hot topic in ARPES on HTSC, the observation of the so called "waterfalls", is addressed. The energy scale at about 0.2-0.3 eV that can be derived from the coherent component of ARPES spectra...
Volkova, O., Vasiliev, A. N., Tristan, N., Richter, J., Schmitt, M., ...
From thermodynamics, LSDA+U calculations and exact diagonalization studies of a five-band Hubbard (Cu 3d, O 2p) model on CuO2 stripes we found that Li2ZrCuO4 (Li2CuZrO4 in traditional notation) is...
Magnetization of undoped 2-leg S = 1/2 spin ladders in La4Sr10Cu24O41 (2006)
Klingeler, R., Hellmann, I., Ribeiro, P., Hess, C., Buechner, B.
Magnetization data of single crystalline La4Sr10Cu24O41 are presented. In this compound, doped spin chains and undoped spin ladders are realized. The magnetization, at low temperatures, is governed...
Zabolotnyy, V. B., Borisenko, S. V., Kordyuk, A. A., Geck, J., Inosov, D., Koitzsch, A., ...
Experimental studies of the electronic structure remain the basic means for understanding the nature of high-temperature superconductivity (HTSC) and testing relevant theoretical models. Appreciable...
One- and Two-Triplon Spectra of a Cuprate Ladder (2006)
Notbohm, S., Ribeiro, P., Lake, B., Tennant, D. A., Schmidt, K. P., Uhrig, G. S., ...
We have performed inelastic neutron scattering on the near ideal spin-ladder compound La4Sr10Cu24O41, which will serve as a model system for the investigation of doped ladders. A key feature in the...
X-ray absorption spectroscopy on layered cobaltates Na_xCoO_2 (2006)
Kroll, T., Knupfer, M., Geck, J., Hess, C., Schwieger, T., Krabbes, G., ...
Measurements of polarization and temperature dependent soft x-ray absorption have been performed on Na_xCoO_2 single crystals with x=0.4 and x=0.6. They show a deviation of the local trigonal...
Schnack, J., Klingeler, R., Kataev, V., Buechner, B.
Magnetization measurements of Sr{14-x}Ca_xCu_{24}O_{41} with 0
Koitzsch, A., Borisenko, S. V., Geck, J., Zabolotnyy, V. B., Knupfer, M., Fink, J., ...
We have investigated the low-energy electronic structure of the strongly correlated one-dimensional copper oxide chain compound SrCuO2 by angle resolved photoemission as a function of excitation...
Unadulterated spectral function of low energy quasiparticles: Bi-2212, nodal direction (2006)
Evtushinsky, D. V., Kordyuk, A. A., Borisenko, S. V., Zabolotnyy, V. B., Knupfer, M., Fink, J., ...
Fitting the momentum distribution photoemission spectra to the Voigt profile appears to be a robust procedure to purify the interaction effects from the experimental resolution. In application to...
Huecker, M., Zimmermann, M. V., Klingeler, R., Kiele, S., Geck, J., Bakehe, S. N., ...
The interplay between crystal symmetry and charge stripe order in Pr1.67Sr0.33NiO4 and Nd1.67Sr0.33NiO4 has been studied by means of single crystal x-ray diffraction. In contrast to tetragonal...
Quenched charge disorder in CuO2 spin chains: Experimental and numerical studies (2006)
Leidl, R., Klingeler, R., Buechner, B., Holtschneider, M., Selke, W.
We report on measurements of the magnetic response of the anisotropic CuO_2 spin chains in lightly hole-doped La_x (Ca,Sr)_14-x Cu_24 O_41, x>=5. The experimental data suggest that in magnetic fields...
Pressure-induced melting of the orbital polaron lattice in La1-xSrxMnO3 (2006)
Klingeler, R., Geck, J., Arumugam, S., Tristan, N., Reutler, P., Buechner, B., ...
We report on the pressure effects on the orbital polaron lattice in the lightly doped manganites $\mathrm{La_{1-x}Sr_xMnO_{3}}$, with $x\sim 1/8$. The dependence of the orbital polaron lattice on...
Magnetic properties of vanadium-oxide nanotubes probed by static magnetization and {51}V NMR (2006)
Vavilova, E., Hellmann, I., Kataev, V., Taeschner, C., Buechner, B., Klingeler, R.
Measurements of the static magnetic susceptibility and of the nuclear magnetic resonance of multiwalled vanadium-oxide nanotubes are reported. In this nanoscale magnet the structural...
"Kinks", Nodal Bilayer Splitting and Interband Scattering in YBCO (2005)
Borisenko, S. V., Kordyuk, A. A., Zabolotnyy, V., Geck, J., Inosov, D., Koitzsch, A., ...
We apply the new-generation ARPES methodology to the most widely studied cuprate superconductor YBCO. Considering the nodal direction, we found noticeable renormalization effects known as "kinks"...
Constituents of the "kink" in high-Tc cuprates (2005)
Kordyuk, A. A., Borisenko, S. V., Zabolotnyy, V. B., Geck, J., Knupfer, M., Fink, J., ...
Applying the Kramers-Kronig consistent procedure, developed earlier, we investigate in details the formation of the quasiparticle spectrum along the nodal direction of high-Tc cuprates. The heavily...
Life of the nodal quasiparticles in Bi-2212 as seen by ARPES (2005)
Kordyuk, A. A., Borisenko, S. V., Koitzsch, A., Fink, J., Knupfer, M., Buechner, B., ...
While the pronounced doping dependence of the quasiparticle spectral weight in the antinodal region of the superconducting cuprates, as seen by ARPES, unambiguously points to the magnetic origin of...
Effect of Zn and Ni impurities on the quasiparticle renormalization in Bi-2212 (2005)
Zabolotnyy, V. B., Borisenko, S. V., Kordyuk, A. A., Fink, J., Geck, J., Koitzsch, A., ...
The Cu substitution by Zn and Ni impurities and its influence on the mass renormalization effects in angle resolved photoelectron spectra (ARPES) of Bi-2212 is addressed. We show that the nonmagnetic...
Orbital polaron lattice formation in lightly doped La1-xSrxMnO3 (2005)
Geck, J., Wochner, P., Kiele, S., Klingeler, R., Reutler, P., Revcolevschi, A., ...
By resonant x-ray scattering at the Mn K-edge on La7/8Sr1/8MnO3, we show that an orbital polaron lattice (OPL) develops at the metal-insulator transition of this compound. This orbital reordering...
Parity of the Pairing Bosons in a High-Temperature Superconductor (2005)
Borisenko, S. V., Kordyuk, A. A., Koitzsch, A., Fink, J., Geck, J., Zabolotnyy, V., ...
We report the observation of a novel effect in the bilayer Pb-Bi2212 high-TC superconductor by means of angle-resolved photoemission with circularly polarized excitation. Different scattering rates,...
Senff, D., Reutler, P., Braden, M., Friedt, O., Bruns, D., Cousson, A., ...
The crystal and magnetic structure of La_{1-x}Sr_{1+x}MnO_4 (0
Kordyuk, A. A., Borisenko, S. V., Koitzsch, A., Fink, J., Knupfer, M., Buechner, B., ...
Studying the nodal quasiparticles in superconducting cuprates by photoemission with highly improved momentum resolution, we show that a new "kink" feature in the scattering rate is a key to uncover...
Dzyaloshinsky-Moriya Spin Canting in the LTT Phase of La2-x-yEuySrxCuO4 (2003)
Huecker, M., Kataev, V., Pommer, J., Ammerahl, U., Revcolevschi, A., Tranquada, J. M., ...
The Cu spin magnetism in La2-x-yEuySrxCuO4 (x
Simovic, B., Nicklas, M., Hammel, P. C., Huecker, M., Buechner, B., Thompson, J. D.
We study the electronic properties of a LaEu0.20Sr0.15CuO4 single crystal under hydrostatic pressure up to 2.9 GPa. Both the freezing of the Cu 3d moments and the structural transition from the...
Ising magnets with mobile defects (2002)
Selke, W., Pokrovsky, V. L., Buechner, B., Kroll, T.
Motivated by recent experiments on cuprates with low-dimensional magnetic interactions, a new class of two-dimensional Ising models with short-range interactions and mobile defects is introduced and...
Magnetic excitations in two-leg spin 1/2 ladders: experiment and theory (2001)
Grueninger, M., Windt, M., Nunner, T., Knetter, C., Schmidt, K. P., Uhrig, G. S., ...
Magnetic excitations in two-leg S=1/2 ladders are studied both experimentally and theoretically. Experimentally, we report on the reflectivity, the transmission and the optical conductivity...
ESR study of (Sr,La,Ca)_{14}Cu_{24}O_{41} (2001)
Kataev, V., Grueninger, M., Ammerahl, U., Buechner, B., Freimuth, A., ...
We report an electron spin resonance (ESR) study of single crystals of the spin-chain spin-ladder compound (Sr,La,Ca)_{14}Cu_{24}O_{41}. The data suggest that in intrinsically hole doped...
Optical spectroscopy of (La,Ca)14Cu24O41 spin ladders: comparison of experiment and theory (2001)
Grueninger, M., Windt, M., Nunner, T., Knetter, C., Schmidt, K. P., Uhrig, G. S., ...
Transmission and reflectivity of La_x Ca_14-x Cu_24 O_41 two-leg spin-1/2 ladders were measured in the mid-infrared regime between 500 and 12000 1/cm. This allows us to determine the optical...
Observation of two-magnon bound states in the two-leg ladders of (Ca,La)14Cu24O41 (2001)
Windt, M., Grueninger, M., Nunner, T., Knetter, C., Schmidt, K., Uhrig, G. S., ...
Phonon-assisted 2-magnon absorption is studied at T=4 K in the spin-1/2 two-leg ladders of Ca_14-x La_x Cu_24 O_41 (x=5 and 4) for polarization of the electrical field parallel to the legs and the...
Hoefener, C., Philipp, J. B., Klein, J., Alff, L., Marx, A., Buechner, B., ...
We have performed a systematic analysis of the voltage and temperature dependence of the tunneling magnetoresistance (TMR) of grain boundaries (GB) in the manganites. We find a strong decrease of the...
The direct Cu NQR Study of the Stripe Phase in the Lanthanum Cuprates (2000)
Teitel'baum, G. B., Buechner, B., De Gronckel, H.
Using Cu NQR in Eu-doped La_(2-x)Sr_xCuO_4 we find the evidence of the pinned stripe phase at 1.3K for 0.08
4f-spin dynamics in La(2-x-y)Sr(x)Nd(y)CuO(4) (1999)
Roepke, M., Holland-Moritz, E., Buechner, B., Berg, H., Lechner, R. E., Longeville, S., ...
We have performed inelastic magnetic neutron scattering experiments on La(2-x-y)Sr(x)Nd(y)CuO(4) in order to study the Nd 4f-spin dynamics at low energies. In all samples we find at high temperatures...
Kataev, V., Validov, A., Huecker, M., Berg, H., Buechner, B.
Measurements of the static magnetization, susceptibility and ESR of Gd spin probes have been performed to study the properties of antiferromagnetically ordered La_{2-x-y}Eu_ySr_xCuO_4 (x less or...
Magnetism of the LTT phase of Eu doped La_{2-x}Sr_xCuO_4 (1997)
Huecker, M., Pommer, J., Buechner, B., Kataev, V., Rameev, B.
The ESR signal of Gd spin probes (0.5 at %) as well as the static normal state susceptibility of Eu (J(Eu^{3+})=0) doped La_{2-x-y}Sr_xEu_yCuO_4 reveal pronounced changes of the Cu magnetism at the...
Kataev, V., Rameev, B., Buechner, B., Huecker, M., Borowski, R.
Measuring the ESR of Gd spin probes we have studied the magnetic properties of the copper oxide planes in the low temperature tetragonal (LTT) phase of Eu doped La_{2-x}Sr_xCuO_4. The data give...
Thermodynamic Properties of the Incommensurate Phase of CuGeO_3 (1996)
Lorenz, T., Ammerahl, U., Ziemes, R., Buechner, B., Revcolevschi, A., Dhalenne, G.
We present high resolution measurements of the specific heat and the thermal expansion of the inorganic spin--Peierls cuprate CuGeO_3 in a magnetic field of 16 Tesla. At the transition from the...