相关论文: Quantum Oscillations in the Underdoped Cuprate YBa…

We present quantum oscillations observed in the heavy fermion compound YbPtBi in magnetic fields far beyond its field-tuned, quantum critical point. Quantum oscillations are observed in magnetic fields as low as 60 kOe at 60 mK and up to…

We succeeded in growing high quality single crystals of the ferromagnetic superconductor UCoGe and measured the magnetoresistance at fields up to 34T. The Shubnikov-de Haas signal was observed for the first time in a U-111 system (UTGe,…

High magnetic fields have revealed a surprisingly small Fermi-surface in underdoped cuprates, possibly resulting from Fermi-surface reconstruction due to an order parameter that breaks translational symmetry of the crystal lattice. A…

We report on the direct probing of the Fermi surface in the bulk of the electron-doped superconductor Nd$_{2-x}$Ce$_x$CuO$_4$ at different doping levels by means of magnetoresistance quantum oscillations. Our data reveal a sharp qualitative…

It is proposed that Fermi-surface reconstruction in electron-doped Ln_{2-x}Ce_xCuO_4 (Ln = Pr, Nd) and in hole-doped YBa_2Cu_3O_{6+y} and YBa_2Cu_4O_8 occurs when the Fermi arcs extend into the second Brillouin zone (BZ). The criterion…

Doping is one of the most relevant paths to tune the functionality of cuprates, it determines carrier density and the overall physical properties of these impressive superconducting materials. We present an oxygen doping study of…

Several decades of debate have centered around the nature of the enigmatic pseudo-gap state in high temperature superconducting copper oxides. Recently, we reported polarized neutron diffraction measurements that suggested the existence of…

Fluctuating superconductivity - vestigial Cooper pairing in the resistive state of a material - is usually associated with low dimensionality, strong disorder or low carrier density. Here, we report single particle spectroscopic,…

We reanalyze the data on the in-plane far infrared conductivity of underdoped orthoII YBa$_{2}$Cu$_{3}$O$_{6.50}$ (YBCO$_{6.50}$) in terms of a model in which a pseudogap opens on part of the Fermi surface with the remaining ungaped piece…

The Weyl semimetal NbP was found to exhibit topological Fermi arcs and exotic magneto-transport properties. Here, we report on magnetic quantum-oscillation measurements on NbP and construct the 3D Fermi surface with the help of…

Detailed structure of the magnetic excitation spectra x"(q,w) of the superconducting oxide YBa2Cu3O6.5(the transition temperature Tc ~ 52 K) in the wave vector (q)- and the energy(w)-space, and its temperature (T) dependence have been…

In the quest for superconductors with high transition temperatures (T$_\mathrm{c}$s), one emerging motif is that unconventional superconductivity is enhanced by fluctuations of a broken-symmetry phase near a quantum-critical point. While…

We present a neutron-scattering study of the static and dynamic spin correlations in the underdoped high-temperature superconductor YBa(2)Cu(3)O(6.45) in magnetic fields up to 15 T. The field strongly enhances static incommensurate magnetic…

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…

To elucidate a quantum phase transition (QPT) in Bi_2Sr_{2-x}La_xCuO_{6+\delta}, we measure charge and heat transport properties at very low temperatures and examine the following characteristics for a wide range of doping: normal-state…

The electronic states near the Fermi level of recently discovered superconductor Ba$_2$CuO$_{4-\delta}$ consist primarily of the Cu $d_{x^2-y^2}$ and $d_{3z^2-r^2}$ orbitals. We investigate the electronic correlation effect and the orbital…

The cuprate superconductor YBa$_2$Cu$_4$O$_8$, in comparison with most other cuprates, has a stable stoichiometry, is largely free of defects and may be regarded as the canonical underdoped cuprate, displaying marked pseudogap behaviour and…

The quantum oscillation data from a whole variety of underdoped HTSC systems and physical measurements has almost universally been presented in very classical terms following the Lifshitz-Kosevich formulation for Fermi-Landau…

We show that a thin film of Weyl or Dirac semimetal with a strong in-plane magnetic field becomes a novel two-dimensional Fermi liquid with interesting properties. The Fermi surface in this system is strongly anisotropic, which originates…

We have investigated the electronic states in quasi one dimensional (1D) CuO chains by microprobe Angle Resolved Photoemission Spectroscopy. We find that the quasiparticle Fermi surface consists of six disconnected segments, consistent with…