相关论文: Angle-dependence of quantum oscillations in YBa2Cu…
We use quantum oscillation measurements to distinguish between spin and orbital components of the lowest energy quasiparticle excitations in YBa2Cu3O6.54, each of which couple differently to a magnetic field. Our measurements reveal the…
The detection of quantum oscillations in the electrical resistivity of YBa2Cu3O6.5 provides direct evidence for the existence of Fermi surface pockets in an underdoped cuprate. We present a theoretical study of the electronic structure of…
The metallic state of the underdoped high-Tc cuprates has remained an enigma: How may seemingly disconnected Fermi surface segments, observed in zero magnetic field as a result of the opening of a partial gap (the pseudogap), possess…
The Fourier transform of the observed magnetic quantum oscillations (MQO) in YBa$_{2}$Cu$_{3}$O$_{6+\delta }$ high-temperature superconductors has a prominent low-frequency peak with two smaller neighbouring peaks. The separation and…
We show that electronic materials with disallowed rotational symmetries that enforce quasiperiodic order can exhibit quantum oscillations and that these are generically associated with exotic "spiral Fermi surfaces." These Fermi surfaces…
Correlation effects in CuO$_2$ layers give rise to a complicated landscape of collective excitations in high-T$_{\rm c}$ cuprates. Their description requires an accurate account for electronic fluctuations at a very broad energy range and…
We report the observation of quantum oscillations in the underdoped cuprate superconductor YBa2Cu4O8 using a tunnel-diode oscillator technique in pulsed magnetic fields up to 85T. There is a clear signal, periodic in inverse field, with…
Arguably the most intriguing aspect of the physics of cuprates is the close proximity between the record high-Tc superconductivity (HTSC) and the antiferromagnetic charge-transfer insulating state driven by Mott-like electron correlations.…
We have studied the electronic structure of electron-doped cuprate superconductors via measurements of high-field Shubnikov-de Haas oscillations in thin films. In optimally doped Pr$_{2-x}$Ce$_{x}$CuO$_{4\pm\delta}$ and…
We give a self-consistent theory of the scale dependent effective mass enhancement m*/m of quasiparticles by 3D antiferromagnetic (AFM) spin fluctuations in the presence of disorder at an AFM quantum critical point. The coupling of…
Fermi surface models applied to the underdoped cuprates predict the small pocket area to be strongly dependent on doping whereas quantum oscillations in YBa2Cu3O6+x find precisely the opposite to be true; seemingly at odds with the…
Shubnikov-de Haas and de Haas-van Alphen effects have been measured in the underdoped high temperature superconductor YBa$_2$Cu$_3$O$_{6.51}$. Data are in agreement with the standard Lifshitz-Kosevitch theory, which confirms the presence of…
In this paper we explore whether the quantum oscillation signals recently observed in ortho-II YBa$_2$Cu$_3$O$_{6.5}$ may be explained by conventional density functional band-structure theory. Our calculations show that the Fermi surface of…
Hole-doped high-temperature cuprate superconductors below optimum doping have small electron-like Fermi surfaces occupying a small fraction of the Brillouin zone. There is strong evidence that this is linked to charge density wave (CDW)…
We summarize our recent theoretical studies on the spin dynamics in the normal state of the metallic cuprates. The contrasting wave vector dependence of the dynamical spin structure factor $S({\bf q}, \omega )$ in LaSrCuO and YBaCuO systems…
Experiments have revealed multiple quantum oscillation frequencies in underdoped high temperature superconductor $\mathrm{YBa_{2}Cu_{3}O_{6+\delta}}$, corresponding to approximately 10% doping, which contain $\mathrm{CuO}$ bilayers in the…
We use magnetic quantum oscillations in the underdoped high Tc superconductor YBa_2Cu_3O_(6+x) (x=0.56) measured over a broad range of temperatures 100 mK<T<18 K to extract the form of the distribution function describing the low-lying…
We consider a two-dimensional Fermi liquid coupled to low-energy commensurate spin fluctuations. At small coupling, the hole Fermi surface is large and centered around $Q =(\pi,\pi)$. We show that as the coupling increases, the shape of the…
The proposed high-spin superconductivity in the half-Heusler compounds changes the landscape of superconductivity research. While superconducting instability is possible only in systems with quantum mechanically coherent quasiparticles, it…
Within Bogoliubov-de Gennes theory, a semiclassical approximation is used to study quantum oscillations and to determine the Fermi surface area associated with these oscillations in a model of a $\pi$-striped superconductor, where the…