Nonlinear characteristics in the magnetoconductance of electron billiards

The effect of an applied bias on transport through an electron billiard is studied by analysis of magnetoconductance fluctuations. It is shown that at low bias, nonlinear effects are well-described by electron heating alone, while at higher bias (V > 2 mV, or approximately 5% of the electron Fermi energy) non-equilibrium effects become significant. We chart this behavior by examining the effective electron temperature plotted against the empirical parameter Q (average energy level spacing over energy level broadening) and the spectral scaling exponent α. The high bias data shows a departure from a curve composed of lattice temperature data for the same device, which indicates a change in electron dynamics within the billiard.