Oleg P. Sushkov

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The main feature in the elastic neutron scattering of La2-xSrxCuO4 is the existence of incommensurate peaks with positions that jump from 45 degrees to 0 degrees at 5% doping. We show that the spiral state of the t-t(')-t('')-J model with realistic parameters describes these data perfectly. We explain why in the insulator the peak is at 45 degrees while it(More)
The phonon Hall effect has been observed in the paramagnetic insulator Tb3Gd5O12. A magnetic field applied perpendicularly to a heat current induces a temperature gradient that is perpendicular to both the field and the current. We show that this effect is due to resonant skew scattering of phonons from the crystal field states of superstoichiometric Tb(3+)(More)
We propose that ordinary semiconductors with large spin-orbit coupling, such as GaAs, can host stable, robust, and tunable topological states in the presence of quantum confinement and superimposed potentials with hexagonal symmetry. We show that the electronic gaps which support chiral spin edge states can be as large as the electronic bandwidth in the(More)
We calculate exactly the vacuum polarization charge density in the field of a subcritical Coulomb impurity, Z|e|/r, in graphene. Our analysis is based on the exact electron Green's function, obtained by using the operator method, and leads to results that are exact in the parameter Zalpha, where alpha is the "fine-structure constant" of graphene. Taking(More)
To explain the experimental spectra for angle resolved photoemission we consider a modified t − J model. The modified model includes next nearest (t′) and next next nearest (t′′) hopping as well as Hubbard model corrections to the spectral weights.A Dyson equation which relates the single hole Green’s functions for a given pseudospin and given spin is(More)
We consider the quantum phase transition between a Néel antiferromagnet and a valence-bond solid (VBS) in a two-dimensional system of S = 1/2 spins. Assuming that the excitations of the critical ground state are linearly dispersing deconfined spinons obeying Bose statistics, we derive expressions for the specific heat C and the magnetic susceptibility χ at(More)
We consider quantum spin systems with dimerization, which at strong coupling have singlet ground states. To account for strong correlations, the S"1 elementary excitations are described as dilute Bose gas with infinite on-site repulsion. This approach is applied to the two-layer Heisenberg antiferromagnet. Our analytic results for the triplet gap, the(More)
We study the behaviour of the electronic chemical potential in YBa2Cu3O6+δ near the superconducting transition using the spin-wave exchange theory of pairing. We find that the experimental value of the jump in the temperature derivative of the chemical potential is inconsistent with the theoretical value calculated under the assumption of constant hole(More)
Starting from the t-J model, we derive the effective field theory describing the spin dynamics in insulating La(2-x)Sr(x)CuO(4), x approximately < 0.055, at low temperature. The theory results in a disordered spiral ground state, in which the staggered component of the copper spins is confined in a plane determined by the spin anisotropies. The static spin(More)