相关论文: A unified theory of superconductivity
To address the issue of the pseudogap in the superconducting state of the high temperature superconducting cuprates, we studied the temperature dependent redistribution of the spectral weight in the \textit{c}-axis polarized optical spectra…
The superconducting gap - an energy scale tied to the superconducting phenomena-opens on the Fermi surface at the superconducting transition temperature (TC) in conventional BCS superconductors. Quite differently, in underdoped high-TC…
In a recent article [Science 317, 1705 (2007)], Anderson pointed out that many theories about electron pairing in cuprate superconductors may be on the wrong track and there is no reason to believe that the dynamic screening (k-space) can…
A pseudogap (PG) was introduced by Mott to describe a state of matter which has a minimum in the density of states at the Fermi level, deep enough for states to become localized. It can arise either from Coulomb repulsion between electrons,…
We present an experimental review of the nature of the pseudogap in the cuprate superconductors. Evidence from various experimental techniques points to a common phenomenology. The pseudogap is seen in all high temperature superconductors…
We present a pairing fluctuation theory which self-consistently incorporates finite momentum pair excitations in the context of BCS--Bose-Einstein condensation (BEC) crossover, and we apply this theory to high $T_c$ superconductors and…
One of the most important outstanding problems in condensed matter physics is determination the ground state of strongly correlated electron system, in particular high-temperature superconductors (HTSC). For these materials, theoretical1-6…
Pursuing higher-temperature superconductors under ambient pressure continues to be a prominent topic in materials discovery. Isomorphic structures like MgB2 exhibit potential for conventional BCS-type superconductivity, but their transition…
Spin-fluctuation-mediated superconductivity is conventionally associated with d_{x^2-y^2} pairing. We show that a generalized model of antiferromagnetic spin fluctuations in three dimensions may also yield a state with formal ``s-wave''…
We present a systematic study of the response properties of two-band (multi-gap) superconductors with spin-singlet (s-wave) pairing correlations, which are assumed to be caused by both intraband (\lambda_{ii}, i=1,2) and interband…
The issue of confinement and bose condensation is studied for gauge models of high-Tc superconductors. First the Abelian-Higgs model in (2+1)D, i.e., XY-model coupled to lattice gauge field $a_{\mu}$ with coupling $g$, is studied taking…
The non-relativistic $G_0 G$ formalism of BCS-BEC crossover at finite temperature is extended to relativistic fermion systems. The uncondensed pairs contribute a pseudogap to the fermion excitations. The theory recovers the BCS mean field…
We investigate the behavior of the superconducting transition temperature within a previously developed BCS-Bose Einstein crossover picture. This picture, based on a decoupling scheme of Kadanoff and Martin, further extended by Patton, can…
Since the discovery of high-temperature superconductivity in the cuprates a theoretical understanding of their phase diagram has remained one of the major outstanding problems in condensed matter physics. Here we propose an effective…
Pseudogap (PG), a phenomenon of opening of gap like features above superconducting (SC) transition temperature (Tc), has been universally observed in the high-Tc cuprates (HTC) (1,2), some heavy fermion superconductors (3), and iron…
A lattice model for strongly interacting electrons motivated by a rank-3 tensor model provides a tool for understanding the pairing mechanism of high-temperature superconductivity. This SYK-like model describes the strange metal phase in…
The BCS theory has been extended by us to the strong-coupling regime where carriers are small lattice polarons and bipolarons. Here I review the multi-polaron strong-coupling theory of superconductivity. Attractive electron correlations,…
London and Campbell penetration depths were measured in single crystals of the endohedral gallide cluster superconductor, Mo$_{8}$Ga$_{41}$. The full temperature range superfluid density is consistent with the clean isotropic $s-$wave…
Results for pseudogaps are obtained from a band model, where the stability of the gap depends on the amplitudes of vibrational displacements, or magnetic moments, and their coupling to electrons. A one-particle gap is favored by normal…
Superconducting mechanism of cuprates is discussed in the light of the proximity of the Mott insulator. The proximity accompanied by suppression of coherence takes place in an inhomogeneous way in the momentum space in finite-dimensional…