Phase Transitions in the Symmetric Kondo Lattice Model in Two and Three Dimensions

TL;DR

This study uses high-order series expansion to analyze phase transitions in the symmetric Kondo lattice model across one, two, and three dimensions, identifying critical points for magnetic ordering.

Contribution

It applies high-order series expansion techniques up to 14th order to the Kondo lattice model in multiple dimensions, revealing phase transition points.

Findings

Evidence for a continuous phase transition from spin liquid to antiferromagnetic order.

Critical coupling estimates: ~0.7 for square lattice, ~0.5 for cubic lattice.

Series expansion up to high order provides detailed insights into phase boundaries.

Abstract

We present an application of high-order series expansion in the coupling constants for the ground state properties of correlated lattice fermion systems. Expansions have been generated up to order $(t/J)^{14}$ for $d=1$ and $(t/J)^8$ for $d=2,\ 3$ for certain properties of the symmetric Kondo lattice model. Analyzing the susceptibility series, we find evidence for a continuous phase transition from the ``spin liquid'' phase characteristic of a ``Kondo Insulator'' to an antiferromagnetically ordered phase in dimensions $d\ge2$ as the antiferromagnetic Kondo coupling is decreased. The critical point is estimated to be at $(t/J)_c\approx0.7$ for square lattice and $(t/J)_c\approx0.5$ for simple-cubic lattice.