ARPES studies of cuprate Fermiology: superconductivity, pseudogap and quasiparticle dynamics

Abstract

We present angle-resolved photoemission spectroscopy (ARPES) studies of the cuprate hightemperature superconductors which elucidate the relation between superconductivity and the pseudogap and highlight low-energy quasiparticle dynamics in the superconducting state. Our experiments suggest that the pseudogap and superconducting gap represent distinct states, which coexist below T c . Studies on Bi-2212 demonstrate that the near-nodal and near-antinodal regions behave differently as a function of temperature and doping, implying that different orders dominate in different momentum-space regions. However, the ubiquity of sharp quasiparticles all around the Fermi surface in Bi-2212 indicates that superconductivity extends into the momentum-space region dominated by the pseudogap, revealing subtlety in this dichotomy. In Bi-2201, the temperature dependence of antinodal spectra reveals particle-hole asymmetry and anomalous spectral broadening, which may constrain the explanation for the pseudogap. Recognizing that electron-boson coupling is an important aspect of cuprate physics, we close with a discussion of the multiple 'kinks' in the nodal dispersion. Understanding these may be important to establishing which excitations are important to superconductivity. PACS numbers:1 arXiv:1009.0274v1 [cond-mat.supr-con] 1 Sep 2010

Hybrid High-Temperature-Superconductor–Semiconductor Tunnel Diode

“…The data is consistent with that expected for an underdoped sample [36]. The pair potential in Bi-2122 is d wave and thus highly anisotropic in the ab plane [37]. Thus, in our c-axis tunneling experiment, an averaged V-shaped gap appears with the maximal value close to 20 mV.…”

d-Wave Superconductivity and s-Wave Charge Density Waves: Coexistence between Order Parameters of Different Origin and Symmetry

“…The depicted "gap roses" show that ARPES angular diagrams represent peculiar combinations of order parameters as angle-dependent combined gaps rather than each order parameter separately (see also recent experimental data in References [100,101], as well as the analysis of photoexcited quasiparticle relaxation dynamics in Reference [98]). The same is true for tunnel and point-contact measurements, where certain tricks are used to single out each order parameter contribution [115,182,239,283].…”

“…By doing this we rely not only on direct observations of CDWs in the real r-space but also on the identification of mysterious pseudogaps (the energy gaps of a still ambiguous nature both below and above the critical temperature, T c ) often observed in high-T c ceramics [100,101,[106][107][108][109][110][111][112] with the CDW gaps. We emphasize that the observed coherent long-range phenomena occur against a non-homogeneous background of the intrinsically non-stoichiometric materials [113][114][115][116][117][118].…”

Strong-coupling analysis of scanning tunneling spectra in Bi2Sr2Ca2CuBerthod1, Fasano2, Maggio-Aprile3 et al. 2013Phys. Rev. B

“…In the case of Bi-2212, values ranging from 1 to 2.5 × 10 7 cm/s as a function of doping have been reported. 86 The variation seen in Fig. 8(d) can therefore be interpreted as reflecting changes in the local doping level.…”