相关论文: Singular Fermi Surfaces I. General Power Counting …

Using the one-loop functional renormalization group technique we evaluate the self-energy in the weak-coupling regime of the 2D t-t' Hubbard model. At van Hove (vH) band fillings and at low temperatures the quasiparticle weight along the…

Properties of the distribution of single-particle levels adjacent to the Fermi surface in finite Fermi systems are studied, focusing on the case in which these levels are degenerate. The interaction of the quasiparticles occupying these…

Many correlated materials display a quantum critical point between a paramagnetic and a SDW state. The SDW wave vector connects points (hot spots) on opposite sides of the Fermi surface. The Fermi velocities at these pairs of points are in…

We study the van der Waals interaction of a metallic or narrow-gap semiconducting nanowire with a surface, in the regime of intermediate wire-surface distances $(v_{F}/c)L \ll d \ll L $ or $L \ll d \ll (c/v_{F})L $, where $L$ is the…

We analyze a two-dimensional Kondo lattice model with special emphasis on non-Hermitian properties of the single-particle spectrum, following a recent proposal by Kozii and Fu. Our analysis based on the dynamical mean-field theory…

When the Fermi surface and the Brillouin zone boundary touch at a Van Hove point, mean-field analysis predicts a ferromagnetic (Stoner) instability at finite $T_{MF}$ for any coupling strength due to the divergent density of states.…

We construct models of excitations about a Fermi surface that display calculable deviations from Fermi liquid behavior in the low-energy limit. They arise as a consequence of coupling to a Chern-Simons gauge field, whose fluctations are…

Electron correlation in cuprates leads to a global constraint $\sum_{\bf k} \Delta_{\bf k} = 0$ on the gap function $\Delta_{\bf k}$ resulting in a gap nodal surface. We give physical arguments supported by numerical results and discuss…

The two-dimensional nature of engineered transition-metal ultra-thin oxide films offers a large playground of yet to be fully understood physics. Here, we study pristine SrVO$_3$ monolayers that have recently been predicted to display a…

We uncover the low-energy spectrum of a t-J model for electrons on a square lattice of spin-1 iron atoms with 3dxz and 3dyz orbital character by applying Schwinger-boson-slave-fermion mean-field theory and by exact diagonalization of one…

We demonstrate a new method to control the Fermi level around the van Hove singularity (VHS) in Li-intercalated graphene on the SiC substrate. By angle-resolved photoemission spectroscopy, we observed a clear Lifshitz transition in the…

We have reproduced band structure calculations from the literature and have used them to analyze in detail the energy landscape around the Fermi level. We found three Van Hove singularities, two below (-230, -54 meV) and one above the Fermi…

The Kondo lattice model with substitutional disorder is studied with attention to the size of the Fermi surface and the associated Dingle temperature. The model serves for understanding heavy-fermion Ce compounds alloyed with La according…

Competing electronic instabilities lie at the heart of emergent phenomena in quantum materials. In low-dimensional metals, Fermi-surface nesting can drive charge density wave (CDW) formation through a Peierls-like mechanism, while in…

Using a two-dimensional Hubbard Hamiltonian for the three electronic bands crossing the Fermi level in Sr$_2$RuO$_4$ we calculate the band structure and spin susceptibility $\chi({\bf q}, \omega)$ in quantitative agreement with nuclear…

Wave kinetic theory has been developed to describe the statistical dynamics of weakly nonlinear, dispersive waves. However, we show that systems which are generally dispersive can have resonant sets of wave modes with identical group…

A defining property of metals is the existence of a Fermi surface: for two dimensions, a continuous contour in momentum space which separates occupied from unoccupied states. In this paper, I discuss angle resolved photoemission data on the…

We consider the dynamic response functions of interacting one dimensional spin-1/2 fermions at arbitrary momenta. We build a non-perturbative zero-temperature theory of the threshold singularities using mobile impurity Hamiltonians. The…

We report an angle-resolved photoemission spectroscopy (ARPES) study of KFe$_2$As$_2$ and CsFe$_2$As$_2$, revealing the existence of a van Hove singularity affecting the electronic properties. As a result of chemical pressure, we find a…

We analyze quantum fluctuation effects at the onset of charge or spin density wave order in two-dimensional metals with an incommensurate $2k_F$ wave vector connecting a single pair of hot spots on the Fermi surface. We compute the momentum…