Photoemission spectrum of Ca2RuO4 : Spin polaron physics in an S=1 antiferromagnet with anisotropies

A Spin-Polaron Technique Utilized on Triangular-Lattice Antiferromagnet

By expressing the Holstein-Primakoff transformation in a symmetric form a modified spin-polaron technique utilized on triangular-lattice antiferromagnet is developed. With the technique, we have treated an extended t-J model, calculated the quasiparticle dispersion, and we also compared the the dispersion with that obtained by other method. PACS: 74.20.-z, 71.27.+a, 75.30.Gw

Dynamics of Small Spin Polaron in the Three-Band Model of Two-Dimensional Spherically Symmetric Antiferromagnet

The retarded Green’s function G(k, ω) of a single small spin polaron in the three-band model for the CuO2 plane is calculated in the self-consistent Born approximation. It is shown that such a spin polaron is a good quasiparticle excitation for realistic values of spin exchange J and effective hopping τ . The polaron spectral density Ap(k, ω) demonstrates small damping in contrast to the result...

Flow Equations and New Weak-Coupling Solution for the Spin-Polaron in a Quantum Antiferromagnet

Sharp photoemission spectra in the quantum antiferromagnet.

The low energy photoemission spectra in quantum antiferromagnets are studied by using several approximation-free calculations and rigorous theorems. The important and measurable property found is that the hole eigenstates with momenta differing by the antiferromagnetic wavevector Q are equivalent and degenerate in energy. However the corresponding eigenstates differs by the presence or the abse...

An Upper Bound for the Spin-Wave Spectrum of the Heisenberg Antiferromagnet

We study the spin-wave spectrum of the Heisenberg antiferromagnet on a bipartite lattice. The spin-wave spectrum on a Néel-ordered ground state is bounded as ε(k) ≤ c|k|, where c gives an upper bound for the spin-wave velocity. In the large-S limit, the upper bound c coincides with the result of the spin-wave theory.