Four-terminal quantum dot as an efficient rectifier of heat and charge currents

We propose an efficient method of heat rectification in a simple system consisting of a quantum dot asymmetrically coupled to four mutually perpendicular electrodes. In such a device, the perpendicular charge and heat currents appear in response to the voltage bias or temperature difference between one pair of electrodes. Even though both longitudinal (along the bias) and perpendicular (to the bias) currents are rectified under appropriate conditions, the rectification factor is typically much bigger for the latter currents. This is true for heat and charge flow. The perpendicular currents are predicted to exist in linear as well as nonlinear transport regimes and require broken mirror symmetry but not time reversal symmetry. The linear effect exists only in geometry which breaks two inversion symmetries along two pairs of electrically coupled terminals. The proposed system is attainable within current technology and provides a novel platform of simultaneous heat and charge management at the nanoscale.