相关论文: Parquet solution for a flat Fermi surface
The repulsive Fermi Hubbard model on the square lattice has a rich phase diagram near half-filling (corresponding to the particle density per lattice site $n=1$): for $n=1$ the ground state is an antiferromagnetic insulator, at $0.6 < n…
It is argued that a superconducting instability appears in the electronic states on the surface of a topological insulator due purely to electromagnetic interactions. The discussion of this instability is based on the analysis of the…
A metallic electron system near an orientational symmetry breaking Pomeranchuk instability is characterized by a ''soft'' Fermi surface with enhanced collective fluctuations. We analyze fluctuation effects in a two-dimensional electron…
The emergence of the Pomeranchuk instability (PI) in a Helical Fermi liquid (HFL) residing on the surface of a three-dimensional topological insulator (3D TI) is addressed at the mean-field level. An expression for the PI condition is…
We present a general framework how to investigate stability of solutions within a single self-consistent renormalization scheme being a parquet-type extension of the Baym-Kadanoff construction of conserving approximations. To obtain a…
Under the framework of the semiclassical theory, we investigate the equilibrium-state properties of a spin polarized dipolar Fermi gas through full numerical calculation. We show that the Fermi surfaces in both real and momentum spaces are…
We study the attractive Hubbard model with spin imbalance on two lattices featuring a flat band: the Lieb and kagome lattices. We present mean-field phase diagrams featuring exotic superfluid phases, similar to the…
In the model considered, the nonlocal interaction of the fermions in different sublattices of a bipartite lattice is introduced. It can also be regarded as local interaction of fermions with opposite ``hypercharge''. The corresponding term…
The mean-field study of the stripe phases of t-t'-U Hubbard model confirms formation of the "impurity" subbands of states localized on domain walls. For bond-aligned stripes it is shown that segments of the Fermi surfaces (FS) in antinodal…
We use renormalization group (RG) analysis and dimensional regularization techniques to study potential superconductivity-inducing four-fermion interactions in systems with critical Fermi surfaces of general dimensions ($m$) and…
We find and characterize the instabilities of the repulsive Hubbard chain in a magnetic field by studing all response functions at low frequency \omega and arbitrary momentum. The instabilities occur at momenta which are simple combinations…
We extend an approximation earlier developed by us for the single-impurity Anderson model to a full-size impurity solver for models of interacting electrons with multiple orbitals. The approximation is based on parquet equations simplified…
We present a new approach to investigate the coexistence of antiferromagnetism and d-wave superconductivity in the two dimensional extended Hubbard model within a numerically exact cluster dynamical mean-field approximation. Self-consistent…
In this study, we examine the superconducting instability of a quasi-one-dimensional lattice in the Hubbard model based on the random-phase approximation (RPA) and the fluctuation exchange (FLEX) approximation. We find that a spin-singlet…
We consider superconductivity in a system with $N$ Fermi surfaces, including intraband and interband effective electron-electron interactions. The effective interaction is described by an $N \times N$ matrix whose elements are assumed to be…
The weak coupling instabilities of a two dimensional Fermi system are investigated for the case of a square lattice using a Wilson renormalization group scheme to one loop order. We focus on a situation where the Fermi surface passes…
One of the fundamental questions about the high temperature cuprate superconductors is the size of the Fermi surface (FS) underlying the superconducting state. By analyzing the single particle spectral function for the Fermi Hubbard model…
Electron-electron interactions can induce Fermi surface deformations which break the point-group symmetry of the lattice structure of the system. In the vicinity of such a "Pomeranchuk instability" the Fermi surface is easily deformed by…
We report on the result of quantum Monte Carlo simulation of quasi-one-dimensional electron systems at 1/4-filling, considering organic superconductors such as TMTSF- and TMTTF-salts. We focus on the effect of dimensionality (interchain…
Several new classes of compounds can be modeled in first approximation by electrons on the triangular lattice that interact through on-site repulsion $U$ as well as nearest-neighbor repulsion $V$. This extended Hubbard model on a triangular…