paper

Hole motion in an arbitrary spin background: Beyond the minimal spin-polaron approximation

arXiv:cond-mat/9708180 · doi:10.1103/PhysRevB.57.3099

Abstract

The motion of a single hole in an arbitrary magnetic background is investigated for the 2D t-J model. The wavefunction of the hole is described within a generalized string picture which leads to a modified concept of spin polarons. We calculate the one-hole spectral function using a large string basis for the limits of a Neel ordered and a completely disordered background. In addition we use a simple approximation to interpolate between these cases. For the antiferromagnetic background we reproduce the well-known quasiparticle band. In the disordered case the shape of the spectral function is found to be strongly momentum-dependent, the quasiparticle weight vanishes for all hole momenta. Finally, we discuss the relevance of results for the lowest energy eigenvalue and its dispersion obtained from calculations using a polaron of minimal size as found in the literature.

13 pages, 8 figures, to appear in Phys. Rev. B

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