Hanbury Brown and Twiss exchange correlations in a graphene box

Abstract

Quadratic detection in linear mesoscopic transport systems produces cross terms that can be viewed as interference signals reflecting statistical properties of charge carriers. In electronic systems these cross term interferences arise from exchange effects due to Pauli principle. Here we demonstrate fermionic Hanbury Brown and Twiss (HBT) exchange phenomena due to indistinguishability of charge carriers in a diffusive graphene system. These exchange effects are verified using current-current cross correlations in combination with regular shot noise (autocorrelation) experiments at microwave frequencies. Our results can be modeled using semiclassical analysis for a square-shaped metallic diffusive conductor, including contributions from contact transparency.The experimentally determined HBT exchange factor values lie between the calculated ones for coherent and hot electron transport.

Shot Noise in Mesoscopic Systems: from Single Particles to Quantum Liquids

“…On the other hand, Oliver et al measured the crosscorrelation between the two outputs of a beam splitter in the time domain [68]. While these HBT experiments were performed using GaAs/AlGaAs semiconductor devices, similar experiments were later conducted using graphene [158,159] and free electrons in a vacuum [160]. Another well-known example of a fermion-quantum-optics experiment is Mach-Zehnder interferometry using QH edge channels [163].…”