Evolution of the Hall Coefficient and the Peculiar Electronic Structure of the Cuprate Superconductors

Abstract

Although the Hall coefficient RH is an informative transport property of metals and semiconductors, its meaning in the cuprate superconductors has been ambiguous because of its unusual characteristics. Here we show that a systematic study of RH in La2−xSrxCuO4 single crystals over a wide doping range establishes a qualitative understanding of its peculiar evolution, which turns out to reflect a two-component nature of the electronic structure caused by an unusual development of the Fermi surface recently uncovered by photoemission experiments.PACS numbers: 74.25. Fy, 74.72.Dn, 74.25.Jb During the past 17 years after the high-T c superconductivity was discovered in cuprates, virtually all measurable properties of their "normal state", the state in the absence of superconductivity, have been studied to understand the stage for novel superconductivity. However, there is yet no established picture for even such basic properties as the resistivity and the Hall coefficient [1], not to mention other more elaborate properties. The Hall coefficient R H of conventional metals is independent of temperature and signifies the Fermi surface (FS) topology and carrier density, but in cuprates R H shows strong, sometimes peaked, temperature dependences as well as a complicated doping dependence. An advance in understanding came when Chien, Wang and Ong found [2] that the cotangent of the Hall angle, cot Θ H (which is the ratio of the in-plane resistivity ρ ab to the Hall resistivity ρ H ), approximately shows a simple linear-in-T 2 behavior, which suggests the existence of a quasiparticlerelaxation rate that changes as ∼ T 2 . However, while it appears that the Hall problem in cuprates can be simplified when analyzed in terms of cot Θ H , it was argued by Ong and Anderson [3] that cot Θ H is after all a derived quantity and the central anomaly resides in the directly measured quantities ρ ab and R H .In this Letter, we address the notoriously difficult problem of the Hall effect with the recent knowledge on the physics of lightly-doped cuprates and the peculiar evolution of the FS recently elucidated by the angle-resolved photoemission spectroscopy (ARPES) experiments [4,5]. We first show that the behavior of R H and ρ ab in the lightly-doped cuprates mimics rather well the behavior of a conventional Fermi liquid, and discuss that this behavior signifies the physics on the "Fermi arc", a small portion of the FS near the Brillouin-zone diagonals. We then discuss that the peculiar hole-doping dependence and the temperature dependence of R H reflect a gradual participation of the "flatband" near (π, 0) of the Brillouin zone, which brings about a sort of two-band nature to the transport. The measurements of R H and ρ ab using a standard six-probe method are done on high-quality single crystals of La 2−x Sr x CuO 4 (LSCO) and YBa 2 Cu 3 O y (YBCO), the details of which have been described elsewhere [6].In slightly hole-doped LSCO and YBCO, which are usually considered to be antiferromagnetic insulators, it was demonstrated [6] th...

Conductivity in Cuprates Arises from Two Different Sources: One-Electron Exchange and Disproportionation

“…The Einstein diffusion model [26] for non-interacting particles is thus invalid in this region. Ando et al [28] have plotted the experimental resistivity from zero to 240 K and found a T 2 behaviour (rather than T 3/2 ). It is unclear whether this disagreement with (17) is significant.…”

d-wave superconductivity in boson+fermion dimer models

“…This was motivated by the need to reconcile transport experiments [13][14][15][16] and photoemission data [17][18][19] in the underdoped region of cuprate superconductors: while photoemission data show Fermi arcs enclosing an area 1 + p (with p being the doping), transport measurements indicate plain Fermi-liquid properties consistent with an area p. In order to resolve this issue and produce a Fermi liquid which encloses an area p, the authors of Refs. [10][11][12] introduced a model for the pseudogap region of the cuprate superconductors which consists of two types of dimers: one spinless bosonic dimer -representing a valence bond between two neighboring spins -and one spin 1/2 fermionic dimer representing a hole delocalized between two sites.…”

Saturation of resistivity and Kohler's rule in Ni-dopedLa1.85Sr0.15CuO4cuprate

“…On the other hand, in cuprates with significant disorder manifested by large residual resistivity ρ res , pure T 2 resistivity dependence has not been reported so far as for Bi 2 Sr 2 CuO 6+δ [3,5,6] or observed only at relatively narrow doping-and T-region as in La 2−x Sr x CuO 4 (LSCO) [3,7]. The clear violation of Kohler's scaling in underdoped LSCO and YBa 2 Cu 3 O 7 [8,9] (although not necessarily meaning breakdown of Fermi-liquid description [10]) has served almost as a hallmark of their peculiar normal-state properties for two decades.…”