Orbital Magnetism of 2D Chaotic Lattices

TL;DR

This paper investigates the orbital magnetism of 2D chaotic lattices, revealing large susceptibility fluctuations and conditions where paramagnetic response exceeds Landau diamagnetism.

Contribution

It provides a theoretical analysis of magnetic response fluctuations in 2D chaotic electron systems using temperature diagrammatic techniques.

Findings

Magnetic susceptibility fluctuations can be very large at low temperatures.

Paramagnetic response can dominate over Landau diamagnetism in certain magnetic field regions.

Fluctuations scale with (k_F l)^{3/2} and can be comparable to or larger than average response.

Abstract

We study the orbital magnetism of 2D lattices with chaotic motion of electrons withing a primitive cell. Using the temperature diagrammatic technique we evaluate the averaged value and rms fluctuation of magnetic response in the diffusive regime withing the model of non-interacting electrons. The fluctuations of magnetic susceptibility turn out to be large and at low temperature can be of the order of $\chi_{L} (k_{F}l)^{3/2}$, where $k_{F}$ is the Fermi wavevector, $l$ is the mean free path, and $\chi_{L}$ is the Landau susceptibility. In the certain region of magnetic fields the paramagnetic contribution to the averaged response is field independent and larger than the absolute value of Landau response.