Orbitally induced string formation in the spin-orbital polarons

Spin, Orbital, and Spin-Orbital Polarons in Transition Metal Oxides

I give a brief overview of a polaron formation in three distinct transition metal oxides: (i) spin polaron when a hole is added to the antiferromagnetic (AF) ordered plane in La2CuO4, (ii) orbital polaron when a hole is added to the alternating orbital (AO) ordered plane in LaMnO3, and (iii) spin-orbital polaron when a hole is added to the AF and AO ordered plane in LaVO3. Comparison of the dis...

Magnetic properties of spin-orbital polarons in lightly doped cobaltates.

We present a numerical treatment of a spin-orbital-polaron model for NaxCoO2 at small hole concentration (0.7 < x 1). We demonstrate how the polarons account for the peculiar magnetic properties of this layered compound: They explain the large susceptibility; their internal degrees of freedom lead both to a negative Curie-Weiss temperature and yet to a ferromagnetic intralayer interaction, ther...

Spin-carrying Spin Polarons in the T-j Model *

The report discusses the spinless-fermion (holon) representation of the t-J model and describes a new analytical representation in which fermion operators are directly related to the physical electron operators and have spin. A simple, leading-order, treatment of the magnetic dynamics allows to take into account the spin-liquid aspect of the ground state. The obtained effective model, in compar...

Spontaneous plaquette formation in the SU(4) spin-orbital ladder.

The low-energy properties of the SU(4) spin-orbital model on a two-leg ladder are studied by a variety of analytical and numerical techniques. As in the case of SU(2) models, there is a singlet-multiplet gap in the spectrum, but the ground state is twofold degenerate. An interpretation in terms of SU(4)-singlet plaquettes is proposed. The implications for general two-dimensional lattices are ou...

Lattice and spin polarons in two dimensions