Ballistic electron transport in macroscopic four-terminal square structures with high mobility

Abstract

Ballistic electron transport characteristics are studied using macroscopic four-terminal square structures formed in high-mobility wafers (μ=7.8×106 cm2/V s at 1.5 K). Ballistic transport over 200 μm can be detected as a negative peak in resistance around B=0 T when four-terminal resistance is measured as a function of magnetic field. The ballistic mean free path (lb) of electrons is evaluated from the size dependence of the negative peak height. The estimated lb becomes 86 μm, which is approximately equal to a conventional mean free path calculated from carrier density and mobility of the wafer.