An efficient thermal diode with ballistic spacer

TL;DR

This paper proposes a thermal diode design using a mass-graded system with diffusive leads and a ballistic spacer, achieving size-independent high rectification efficiency suitable for thermal management applications.

Contribution

It introduces a novel thermal diode structure with a ballistic spacer that maintains large rectification regardless of system size, advancing thermal device design.

Findings

Large thermal rectification factor independent of system size

Effective thermal gradient is size-independent

Robustness of the diode across parameter variations

Abstract

Thermal rectification is of importance not only for fundamental physics, but also for potential applications in thermal manipulations and thermal management. However, thermal rectification effect usually decays rapidly with system size. Here, we show that a mass-graded system, with two diffusive leads separated by a ballistic spacer, can exhibit large thermal rectification effect, with the rectification factor independent of system size. The underlying mechanism is explained in terms of the effective size-independent thermal gradient and the match/mismatch of the phonon bands. We also show the robustness of the thermal diode upon variation of the model's parameters. Our finding suggests a promising way for designing realistic efficient thermal diodes.