On-demand electron source with tunable energy distribution

Abstract

We propose a scheme to manipulate the electron-hole excitation in the voltage pulse electron source, which can be realized by a voltage-driven Ohmic contact connecting to a quantum hall edge channel. It has been known that the electron-hole excitation can be suppressed via Lorentzian pulses, leading to noiseless electron current. We show that, instead of the Lorentzian pulses, driven via the voltage pulse $V(t) = 2 \frac{\hbar}{e} \sqrt{\frac{\sqrt{3}}{\pi} k_{\rm B} T_h} \arctanh( \frac{t - t_0}{t_0} )$ with duration $t_0$, the electron-hole excitation can be tuned so that the corresponding energy distribution of the emitted electrons follows the Fermi distribution with temperature $T_{\rm D} = \sqrt{ T^2_{\rm S} + T^2_{\rm h} }$, with $T_{\rm S}$ being the electron temperature in the Ohmic contact. Such Fermi distribution can be established without introducing additional energy relaxation mechanism and can be detected via shot noise thermometry technique, making it helpful in the study of thermal transport and decoherence in mesoscopic system.