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1.
A.A. Kordyuk V.B. Zabolotnyy D.V. Evtushinsky D.S. Inosov T.K. Kim B. Büchner S.V. Borisenko 《The European physical journal. Special topics》2010,188(1):153-162
We review the search for a mediator of high-T
c superconductivity focusing on ARPES experiment. In case of HTSC cuprates, we summarize and discuss a consistent view of electronic
interactions that provides natural explanation of both the origin of the pseudogap state and the mechanism for high temperature
superconductivity. Within this scenario, the spin-fluctuations play a decisive role in formation of the fermionic excitation
spectrum in the normal state and are sufficient to explain the high transition temperatures to the superconducting state while
the pseudogap phenomenon is a consequence of a Peierls-type intrinsic instability of electronic system to formation of an
incommensurate density wave. On the other hand, a similar analysis being applied to the iron pnictides reveals especially
strong electron-phonon coupling that suggests important role of phonons for high-T
c superconductivity in pnictides. 相似文献
2.
CM Thaker S Rayaprol Krushna Mavani DS Rana MS Sahasrabudhe SI Patil DG Kuberkar 《Pramana》2002,58(5-6):1035-1039
The effect of simultaneous substitution of a fluctuating cation and a divalent cation in LaMnO3 perovskite modifies the properties of the material to exhibit large valence colossal magnetoresistance (CMR) effect. A good
example of these properties is (La1−2x
Pr
x
Ca
x
)MnO3 (LPCMO) type CMR material. In this communication it is reported that, with the increase in x (for x=0.1, 0.15, 0.2), the T
c varies between 100 and 120 K with improvisation in metal-insulator transition. Interestingly, resistance increases with x from few hundred ohms to few kilo ohms with corresponding decrease in the unit cell volume. The results of the studies using
X-ray diffraction (XRD), electrical resistivity, magnetoresistance and ac susceptibility measurements on LPCMO samples for
understanding the structural, transport and magnetic properties are discussed in detail. 相似文献
3.
4.
Evtushinsky DV Kordyuk AA Zabolotnyy VB Inosov DS Büchner B Berger H Patthey L Follath R Borisenko SV 《Physical review letters》2008,100(23):236402
We present a calculation of the Hall coefficient in 2H-TaSe(2) and 2H-Cu(0.2)NbS(2) based on their electronic structure extracted from angle-resolved photoemission spectra. The well-known semiclassical approach, based on the solution of the Boltzmann equation, yields the correct value for the normal-state Hall coefficient. Entering the charge density wave state results in the opening of the pseudogap and redistribution of the spectral weight. Accounting for this allows us to reproduce the temperature dependence of the Hall coefficient, including the prominent sign change, with no adjustable parameters. 相似文献
5.
Park JT Friemel G Li Y Kim JH Tsurkan V Deisenhofer J Krug von Nidda HA Loidl A Ivanov A Keimer B Inosov DS 《Physical review letters》2011,107(17):177005
We have studied the low-energy spin-excitation spectrum of the single-crystalline Rb(2)Fe(4)Se(5) superconductor (T(c)=32 K) by means of inelastic neutron scattering. In the superconducting state, we observe a magnetic resonant mode centered at an energy of ?ω(res)=14 meV and at the (0.5 0.25 0.5) wave vector (unfolded Fe-sublattice notation), which differs from the ones characterizing magnetic resonant modes in other iron-based superconductors. Our finding suggests that the 245-iron selenides are unconventional superconductors with a sign-changing order parameter, in which bulk superconductivity coexists with the √5×√5 magnetic superstructure. The estimated ratios of ?ω(res)/k(B)T(c)≈5.1±0.4 and ?ω(res)/2Δ≈0.7±0.1, where Δ is the superconducting gap, indicate moderate pairing strength in this compound, similar to that in optimally doped 1111 and 122 pnictides. 相似文献
6.
Inosov DS Fink J Kordyuk AA Borisenko SV Zabolotnyy VB Schuster R Knupfer M Büchner B Follath R Dürr HA Eberhardt W Hinkov V Keimer B Berger H 《Physical review letters》2007,99(23):237002
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 Fermi level and 1 eV binding energy in several high-T_{c} superconductors. We observe strong changes of the dispersion between different Brillouin zones and a strong dependence on the photon energy around 75 eV, which we associate with the resonant photoemission at the Cu3p-->3d_{x;{2}-y;{2}} edge. We conclude that the high-energy "waterfall" dispersion results from a strong suppression of the photoemission intensity at the center of the Brillouin zone due to matrix element effects and is, therefore, not an intrinsic feature of the spectral function. This indicates that the new high-energy scale in the electronic structure of cuprates derived from the waterfall-like dispersion may be incorrect. 相似文献
7.
V.B. Zabolotnyy D.V. Evtushinsky A.A. Kordyuk D.S. Inosov A. Koitzsch A.V. Boris G.L. Sun C.T. Lin M. Knupfer B. Büchner A. Varykhalov R. Follath S.V. Borisenko 《Physica C: Superconductivity and its Applications》2009,469(9-12):448-451
Here we apply high resolution angle-resolved photoemission spectroscopy (ARPES) using a wide excitation energy range to probe the electronic structure and the Fermi surface topology of the Ba1?xKxFe2As2 (Tc = 32 K) superconductor. We find significant deviations in the low energy band structure from that predicted in calculations. A set of Fermi surface sheets with unexpected topology is detected at the Brillouin zone boundary. At the X-symmetry point the Fermi surface is formed by a shallow electron-like pocket surrounded by four hole-like pockets elongated in Γ?X and Γ?Y directions. 相似文献
8.
Evtushinsky DV Inosov DS Urbanik G Zabolotnyy VB Schuster R Sass P Hänke T Hess C Büchner B Follath R Reutler P Revcolevschi A Kordyuk AA Borisenko SV 《Physical review letters》2010,105(14):147201
The single-layered half-doped manganite La(0.5)Sr(1.5)MnO? (LSMO), was studied by means of the angle-resolved photoemission spectroscopy (ARPES), scanning tunneling microscopy (STM), and resistivity measurements. STM revealed a smooth reconstruction-free surface; the density of states, extracted from photoemission and tunneling spectroscopy, is in agreement with transport measurements. The derived from ARPES Fermi surface (FS) nesting properties correspond to the known pattern of the charge-orbital ordering (COO), which implies that FS instability is related to the propensity to form a COO state in LSMO. 相似文献
9.
Borisenko SV Kordyuk AA Zabolotnyy V Geck J Inosov D Koitzsch A Fink J Knupfer M Büchner B Hinkov V Lin CT Keimer B Wolf T Chiuzbăian SG Patthey L Follath R 《Physical review letters》2006,96(11):117004
We apply the new-generation angle-resolved photoemission spectroscopy methodology to the most widely studied cuprate superconductor YBa2Cu3O(6+x). Considering the nodal direction, we found noticeable renormalization effects known as kinks both in the quasiparticle dispersion and scattering rate, the bilayer splitting, and evidence for strong interband scattering--all the characteristic features of the nodal quasiparticles detected earlier in Bi2Sr2CaCu2O(8+delta). The typical energy scale and the doping dependence of the kinks clearly point to their intimate relation with the spin-1 resonance seen in the neutron scattering experiments. Our findings strongly suggest a universality of the electron dynamics in the bilayer superconducting cuprates and a dominating role of the spin fluctuations in the formation of the quasiparticles along the nodal direction. 相似文献
10.
D.S. Inosov 《物理学进展》2013,62(3):149-252
The discovery of magnetism by the ancient Greeks was enabled by the natural occurrence of lodestone – a magnetized version of the mineral magnetite. Nowadays, natural minerals continue to inspire the search for novel magnetic materials with quantum-critical behaviour or exotic ground states such as spin liquids. The recent surge of interest in magnetic frustration and quantum magnetism was largely encouraged by crystalline structures of natural minerals realizing pyrochlore, kagome, or triangular arrangements of magnetic ions. As a result, names like azurite, jarosite, volborthite, and others, which were barely known beyond the mineralogical community a few decades ago, found their way into cutting-edge research in solid-state physics. In some cases, the structures of natural minerals are too complex to be synthesized artificially in a chemistry lab, especially in single-crystalline form, and there is a growing number of examples demonstrating the potential of natural specimens for experimental investigations in the field of quantum magnetism. On many other occasions, minerals may guide chemists in the synthesis of novel compounds with unusual magnetic properties. The present review attempts to embrace this quickly emerging interdisciplinary field that bridges mineralogy with low-temperature condensed-matter physics and quantum chemistry. 相似文献