Related papers: Spin fluctuations and high-temperature superconduc…
The t-J model is a paradigmatic model for the study of strongly correlated electron systems. In particular, it has been argued that it is an appropriate model to describe the cuprate high-Tc superconductors. It turns out that a…
Hund's pairing refers to Cooper pairing generated by onsite interactions that become attractive due to large Hund's exchange $J$. This is possible in multiorbital systems even when all local bare interactions are repulsive, since attraction…
We demonstrate that many features ascribed to strong correlation effects in various spectroscopies of the cuprates are captured by a calculation of the self-energy incorporating effects of spin and charge fluctuations. The self energy is…
It is expected that at weak to intermediate coupling, d-wave superconductivity can be induced by antiferromagnetic fluctuations. However, one needs to clarify the role of Fermi surface topology, density of states, pseudogap, and wave vector…
Strongly correlated electron systems host a variety of poorly understood correlations in their high temperature normal state. Unlike ordered phases defined by order parameters, these normal state phases are often defined through…
Theories based on the coupling between spin fluctuations and fermionic quasiparticles are among the leading contenders to explain the origin of high-temperature superconductivity, but estimates of the strength of this interaction differ…
We present a novel pairing mechanism for superconductivity in strongly correlated electron systems, which often have both localised and itinerant charge carriers. An effective anisotropic interaction between the itinerant particles…
We consider the magnetic properties of high Tc cuprates from a gauge theory point of view, with emphasis on the underdoped regime. Underdoped cuprates possess certain antiferromagnetic correlations, as evidenced, for example, by different…
Recent experimental and theoretical developments in high-temperature superconductivity are reviewed, and the empirically asymmetric behavior between hole-doped and electron-doped cuprates is contrasted. A number of phenomena previously…
The origin of high-temperature superconductivity in cuprates is still an unresolved issue. Among the most likely candidates for mediating the Cooper pair condensate are spin fluctuations and the electron-phonon interaction. While the former…
The recent development of x-ray scattering techniques revealed the charge-excitation spectrum in high-$T_c$ cuprate superconductors. While the presence of a dispersive signal in the high-energy charge-excitation spectrum is well accepted in…
We propose an explanation of several experimental features related to the ``pseudogap'' in HTS cuprates in terms of a spin-charge gauge theory approach to the t-J model. The metal-insulator crossover as temperature decreases is explained…
Spin fluctuations enter the calculation of the superconducting transition temperature T$_c$ only in the next-to-leading order (i.e., in O(1/N$^2$) of the 1/N expansion of the t-J model. We have calculated these terms and show that they have…
One central challenge in high-$T_c$ superconductivity (SC) is to derive a detailed understanding for the specific role of the $Cu$-$d_{x^2-y^2}$ and $O$-$p_{x,y}$ orbital degrees of freedom. In most theoretical studies an effective one-band…
Within the framework of the kinetic energy driven superconducting mechanism, the dynamical spin response of cuprate superconductors is studied from low-energy to high-energy. The spin self-energy is evaluated explicitly in terms of the…
A general multi-orbital Hubbard model, which includes on-site inter-orbital electron hoppings, is introduced and studied. It is shown that the on-site inter-orbital single electron hopping is one of the most basic interactions. Two electron…
We investigate the spectral properties of the doped ${t-t'}$ Hubbard model with parameters typical for high-temperature cuprate superconductors. Our approach is based on a novel strong-coupling Green's function expansion around a reference…
We utilize the Hubbard model to demonstrate that doping of the antiferromagnetic parent compounds of cuprate superconductors stabilizes a spin liquid state. Superconductivity in such a state emerges due to the spin-orbit coupling between…
An electron-phonon interaction arising from the modulation of the superexchange interaction by phonons is studied within the theoretical framework of Kondo lattices. It is relevant in strongly correlated electron liquids in cuprate oxide…
The challenge of understanding high-temperature superconductivity has led to a plethora of ideas, but 30 years after its discovery in cuprates, very few have achieved convincing experimental validation. While Hubbard and t-J models were…