Continuous quantum phase transition in a Kondo lattice model

TL;DR

This paper investigates the quantum phase transition in an anisotropic Kondo lattice model, revealing a first-order transition at finite temperature and a continuous, locally critical transition at zero temperature using advanced theoretical methods.

Contribution

It introduces an extended dynamical mean field theory combined with quantum Monte Carlo to study magnetic transitions in the Kondo lattice model at very low temperatures.

Findings

Finite-temperature transition is first order.

Zero-temperature transition is continuous and locally critical.

Method effectively captures low-temperature quantum critical behavior.

Abstract

We study the magnetic quantum phase transition in an anisotropic Kondo lattice model. The dynamical competition between the RKKY and Kondo interactions is treated using an extended dynamic mean field theory (EDMFT) appropriate for both the antiferromagnetic and paramagnetic phases. A quantum Monte Carlo approach is used, which is able to reach very low temperatures, of the order of 1% of the bare Kondo scale. We find that the finite-temperature magnetic transition, which occurs for sufficiently large RKKY interactions, is first order. The extrapolated zero-temperature magnetic transition, on the other hand, is continuous and locally critical.