Related papers: Pseudogap phase formation in the crossover from Bo…
A phase diagram for a 2D metal with variable carrier density has been derived. It consists of a normal phase, where the order parameter is absent; a so-called ``abnormal normal'' phase where this parameter is also absent but the mean number…
It is shown that in 2D system of the fermions with simplest indirect boson-induced attraction (through the Einstein phonon exchange as an example) along with the normal and superconducting phases there arises a new (called "abnormal normal"…
A phase diagram for a quasi-2D metal with variable carrier density has been derived. The phases present are the normal phase, where the order parameter is zero; the pseudogap phase where the absolute value of the order parameter is non-zero…
Two-dimensional system of the fermions with the indirect Einstein phonon-exchange attraction and added local four-fermion interaction is considered. It is shown that in such a system at resulting attraction between particles a new…
The condensation of paired fermions into superfluid states changes progressively depending on the coupling strength. At the midpoint of the crossover between Bardeen--Cooper--Schrieffer (BCS) weak-coupling and Bose--Einstein condensate…
This article reviews the current status of precursor superconducting phase fluctuations as a possible mechanism for pseudogap formation in high-temperature superconductors. In particular we compare this approach which relies on the…
We describe the approach of the superconducting state as a sequence of cross-over phenomena. As the temperature is decreased, uncorrelated pairing of the electrons leads to the opening of a pseudogap at T_F^*. Upon further lowering the…
The presence of nonmagnetic impurities in a 2D ``bad metal'' depresses the superconducting Berezinskii-Kosterlitz-Thouless transition temperature, while leaving the pairing energy scale unchanged. Thus the region of the pseudogap…
The normal state behaviour of the density of states of the electrons described by the BOSON - FERMION model for Bose-Einstein condensation driven superconductivity is characterized by the appearence of a pseudogap which developes into a…
We examine the effects of a phenomenological pseudogap on the T=0 K phase diagram of a high temperature superconductor within a self-consistent model which exhibits a d-wave pairing symmetry. At the mean-field level the presence of a…
A reduction of the density of states near the Fermi energy in the normal state (pseudogap) of high-temperature oxide superconductors is examined on the basis of the two-dimensional tight-binding model with effective interactions due to…
We study the phase fluctuations in the normal state of generic two-dimensional superconducting systems with s-wave pairing. The effect of phase fluctuations of the pairing fields can be dealt with perturbatively using disorder averaging,…
Pseudogap formation is an ubiquitous phenomena in strongly-correlated superconductors, for example cuprates, heavy-fermion superconductors, and iron pnictides. As the system is cooled, an energy gap opens in the excitation spectrum before…
We investigate strong-coupling properties of a two-dimensional ultracold Fermi gas in the normal phase. In the three-dimensional case, it has been shown that the so-called pseudogap phenomena can be well described by a (non-self-consistent)…
This article gives a contemporary and to some extent pedagogical review of the current theoretical understanding of the formation of the superconducting state in metallic systems with a variable density of carriers. We make an attempt to…
The anomalous properties of High-$T_{{\rm c}}$ cuprates are investigated both in the normal state and in the superconducting state. In particular, we pay atte ntion to the pseudogap in the normal state and the phase transition from the pse…
The superconducting phase of the high-Tc cuprates has been thought to be described by a single d-wave pairing order parameter. Recently, there has been growing evidence suggesting that another form of order, possibly inherited from the…
The existence of a pseudogap above the critical temperature has been widely used to explain the anomalous behaviour of the normal state of high-temperature superconductors. In two dimensions the existence of a pseudogap phase has already…
This thesis deals with the Hubbard model as prototypical model to describe the physics of electrons in the two-dimensional copper-oxide planes of high-$T_c$ cuprates. To get approximate solutions, we employ functional renormalization group…
More recently STM experimets present firm evidence of some kind of charge modulation in underdoped cuprates. The peculiar observations of the above experiments are located in the so called pseudo-gap region of the phase diagram, just over…