Anisotropic scattering and anomalous normal-state transport in a high-temperature superconductor

Abstract

T he metallic state of high-temperature copper-oxide superconductors, characterized by unusual and distinct temperature dependences in the transport properties 1-4 , is markedly different from that of textbook metals. Despite intense theoretical efforts 5-11 , our limited understanding is impaired by our inability to determine experimentally the temperature and momentum dependence of the transport scattering rate. Here, we use a powerful magnetotransport probe to show that the resistivity and the Hall coefficient in highly doped Tl 2 Ba 2 CuO 6+δ originate from two distinct inelastic scattering channels. One channel is due to conventional electronelectron scattering; the other is highly anisotropic, has the same symmetry as the superconducting gap and a magnitude that grows approximately linearly with temperature. The observed form and anisotropy place tight constraints on theories of the metallic state. Moreover, in heavily doped non-superconducting La 2−x Sr x CuO 4 , this anisotropic scattering term is absent 12 , suggesting an intimate connection between the origin of this scattering and superconductivity itself.The in-plane properties of layered metals can sometimes be obtained from measurements of out-of-plane quantities. For example, angular magnetoresistance oscillations (AMRO), which are angular variations in the interlayer resistivity ρ ⊥ induced by rotating a magnetic field H in a polar plane relative to the conducting layers, can provide detailed information on the shape of the in-plane Fermi surface (FS) in layered metals. Here we resolve for the first time, the momentum (k) and energy (ω or T) dependence of the in-plane transport lifetime τ in an overdoped cuprate Tl 2 Ba 2 (Ca 0 )Cu 1 O 6+δ (Tl2201) through advances, both experimental and theoretical, in the AMRO technique. Experimentally, we extend the temperature range of previous AMRO measurements on overdoped Tl2201 13 (with a superconducting transition temperature T c = 15 K) by more than one order of magnitude. Theoretically, we derive a new general analytical expression for the interlayer conductivity σ ⊥ in a tilted H that incorporates basal-plane anisotropy. For T > 4 K, the AMRO can only be explained by inclusion of an anisotropic scattering rate 1/τ whose anisotropy grows with T. Significantly, the anisotropy in 1/τ and its T dependence up to 55 K can quantitatively account for both the robust linear-in-T component to the in-plane resistivity ρ ab and the T-dependent Hall coefficient R H over the same temperature range 14,15 . These anomalous behaviours are not characteristic of a simple Fermi liquid, which is often the starting point for modelling overdoped cuprates. We discuss the consequences of these findings for our understanding of the normal-state transport in cuprates.As described in the Supplementary Information, detailed azimuthal and polar-angle-dependent AMRO data were taken at 4.2 K and 45 T and fitted to the Shockley-Chambers tube integral form of the Boltzmann transport equation, modified for a quasitwo-dimensional (quasi...

Anisotropic breakdown of Fermi liquid quasiparticle excitations in overdoped La2−xSrxCuO4

“…This is consistent with angledependent magneto-resistance experiments on overdoped Tl2201 4 . ARPES experiments on overdoped Tl2201 have, however, reported the opposite trend 29 .…”

“…The breakdown of this concept has therefore been studied in great detail by transport and thermodynamic measurements [2][3][4][5][6][7][8][9][10] . A common assumption is that the Fermi liquid self-energy ImS is local, that is, that it depends only on excitation energy o:…”

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

“…Evidently, α 1 is not sensitive to disappearing of the antinodal regions during degradation/reconstruction of large Fermi surface into arcs/pockets. The linear-in-T scattering is anisotropic in CuO 2 plane [50] and its maximal level at (π,0) for α 1 =1 µΩcm/K is comparable [35] with Planckian dissipation limit [51,52]. Decoherence of quasiparticle states beyond this limit seems to be plausible explanation [35] of negligible role of antinodal states in the conductivity.…”

Sensitivity of the interlayer magnetoresistance of layered metals to intralayer anisotropies

“…The dependence of the interlayer magnetoresistance on the magnetic field direction has been used to map out a threedimensional ͑3D͒ FS in a chemically diverse range of layered metals, including organic charge transfer salts, 7,8 ruthenates, 9,10 semiconductor heterostructures, 11 tungsten bronzes, 12 intercalated graphite, 13 and an overdoped thallium cuprate. 14,15 However, most of the observed angle dependent magnetoresistance oscillations ͑AMROs͒ are also consistent with a two-dimensional FS, i.e., a FS existing only within the individual layers and weakly incoherent interlayer transport. 16 Hence, it is difficult to experimentally distinguish the two physically distinct pictures summarized in Fig.…”

“…͑9͒ and its significance, we fit recent AMRO measurements of a thallium cuprate. 14,15 An important point to note about these experiments is that the data are of very high quality and it is thus possible to fit AMRO to very high precision, which leads to extraction of FS parameters to high accuracy.…”