Magnetoresistance in a soft billiard: giant peak near the percolation threshold

TL;DR

This study uses numerical simulations to reveal a giant magnetoresistance peak near the percolation threshold in a two-dimensional electron system, linked to the topology of the potential landscape.

Contribution

It uncovers a previously unobserved sharp peak in magnetoresistance just below the percolation threshold, relating it to the topology of equipotential lines.

Findings

Resistance increases up to 15 times near the threshold

Giant peak occurs just below the percolation point

Peak is associated with infinite equipotential lines

Abstract

By numerical simulation, we study the classical magnetoresistance of two-dimensional electrons in the presence of weak short range scattering. A critical magnetic field defines the percolation threshold, above which the longitudinal resistance vanishes. Unexpectedely, just below this threshold we find a shrp narrow peak, where the resistance may increase 15 times compared to its zero-field value. By considering the complex topology of the effective potential landscape for the center of the cyclotron circle, we show that this phenomenon is related to infinite equipotential lines, which exists only in a narrow magnetic field interval below the percolation threshold