Cumulant approach to weakly doped antiferromagnets

Article

关键词: T-J MODEL;    QUANTUM ANTIFERROMAGNET;    SPECTRAL-FUNCTION;    GROUND-STATE;    SINGLE-HOLE;    SPIN-WAVES;    SUPERCONDUCTIVITY;    EXCITATIONS;    INSULATORS;    MOTION;   

DOI  :  10.1103/PhysRevB.54.15483

来源: SCIE

【 摘 要 】

We present an approach to static and dynamical properties of holes and spins in weakly doped antiferromagnets in two dimensions. The calculations are based on a recently introduced cumulant approach to groundstate properties of correlated electronic systems. The present method allows us to evaluate hole ana spin-wave dispersion relations by considering hole or spin excitations of the ground state. Usually, these dispersions are found from time-dependent correlation functions. To demonstrate the ability of the approach we first derive the dispersion relation for the lowest single hole excitation at half-filling. However, the main purpose of this paper is to focus on the mutual influence of mobile holes and spin waves in the weakly doped system. It is shown that low-energy spin excitations strongly admix to the ground state. The coupling of spin waves and holes leads to a strong suppression of the staggered magnetization which cannot be explained by a simple rigid-band picture for the hole quasiparticles. Also the experimentally observed doping dependence of the spin-wave excitation energies can be understood within our formalism.

【 授权许可】

Free