Related papers: Phenomenological Three-Orbital Spin-Fermion Model …
We consider spin and electronic properties of itinerant electron systems, described by the spin-fermion model, near the antiferromagnetic critical point. We expand in the inverse number of hot spots in the Brillouin zone, N and present the…
We use quantum Monte Carlo to determine the magnetic and transport properties of coupled square lattice spin and fermionic planes as a model for a metal-insulator interface. Specifically, layers of Ising spins with an intra-layer exchange…
The double exchange model with on-site Coulomb repulsion is considered. Schwinger-bosons representation of the localized spins is used and two spin-singlet Fermion operators are introduced. In terms of the new Fermi fields the on-site…
A microscopic theory of spin excitations in strongly-correlated electronic systems within the t-J model is discussed. An exact representation for the dynamic spin susceptibility is derived. In the normal state, the excitation spectrum…
We present a lattice field theory of spins coupled to Dirac fermions, as a model for the doped copper oxide compounds. Both the fermionic and spin degrees of freedom are treated dynamically. The influence of the charge carriers on the…
The influence of spin and charge fluctuations on spectra of the two-dimensional fermionic Hubbard model is considered using the strong coupling diagram technique. Infinite sequences of diagrams containing ladder inserts, which describe the…
A model of superconductivity in layered high-temperature superconducting cuprates is proposed, based on the extended saddle point singularities in the electron spectrum, weak screening of the Coulomb interaction and phonon-mediated…
We use the coupled 2d-spin-3d-fermion model proposed by Rosch {\sl et. al.} (Phys. Rev. Lett. {\bf 79}, 159 (1997)) to study the thermoelectric behaviour of a heavy fermion compound when it is close to an antiferromagnetic quantum critical…
Starting from the three-band Hubbard model for the cuprates, we calculate analytically the four-spin cyclic exchange in the limit of infinite on-site Coulomb repulsion and zero O-O hopping $t_{pp}$ using two methods: i) perturbation theory…
The magnetic properties of a variety of materials with promise for technological applications have been described by models in which fermions are coupled to local moment spins. Monte Carlo studies of such models usually ignore…
We compute the electron spin susceptibility in the pseudogap regime of the two-dimensional Hubbard model in the framework of a SU(2) gauge theory of fluctuating magnetic order. The electrons are fractionalized in fermionic chargons with a…
We derive in detail a novel solution of the spin fermion model which is valid in the quasi-static limit pi T<<omega_sf, found in the intermediate (pseudoscaling) regime of the magnetic phase diagram of cuprate superconductors, and use it to…
Thermodynamic and dynamical properties of a model of Dirac fermions with a deconfined quantum critical point (DQCP) separating an interaction-generated quantum spin-Hall insulator from an s-wave superconductor [Nature Comm.~{\bf 10}, 2658…
We comment on a recent paper [Phys. Rev. Lett. 97, 070401 (2006): quant-ph/0603229] concerning rubidium atoms trapped near a superconducting niobium surface at ~4K. This seeks to calculate the rate of atomic spin flips induced by thermal…
A spin-charge recombination route to superconductivity, proposed earlier (1992)], is examined using the Schwinger boson representation of the t-J model. The representation is known to work well at half-filling. It was shown in the earlier…
Electron interactions are pivotal for defining the electronic structure of quantum materials. In particular, the strong electron Coulomb repulsion is considered the keystone for describing the emergence of exotic and/or ordered phases of…
Recently discovered advanced materials, such as heavy fermions, frequently exhibit a rich phase diagram suggesting the presence of different competing interactions. A unified description of the origin of these multiple interactions, albeit…
We propose a model for high-T$_{c}$ superconductors, valid for $0\leq\delta\leq\delta_{SC}$, that includes both the spin fluctuations of the Cu$^{++}$ magnetic ions and of the O$^{--}$ doped holes. Spin-charge separation is taken into…
A method for Monte Carlo simulation of 2D spin-polarized electron transport in III-V semiconductor heterojunction FETs is presented. In the simulation, the dynamics of the electrons in coordinate and momentum space is treated…
Electron transport in a finite one dimensional quantum spin chain (with ferromagnetic exchange) is studied within an $s-d$ exchange Hamiltonian. Spin transfer coefficients strongly depend on the sign of the $s-d$ exchange constant. For a…