Heat transfer at the van der Waals interface between graphene and NbSe2

TL;DR

This study investigates heat transfer at the van der Waals interface between graphene and NbSe2, revealing how electron heating in graphene affects NbSe2's superconductivity and can be modulated electrically.

Contribution

It demonstrates the impact of heat transfer through vdW interfaces on superconducting properties and introduces electric field control of critical current via graphene electrodes.

Findings

Critical current of NbSe2 decreases with graphene electrode compared to Au/Ti.

Electron heating in graphene modulates NbSe2's superconductivity.

Heat transfer at vdW interface influences electronic properties of 2D materials.

Abstract

Graphene has been widely used to construct low-resistance van der Waals (vdW) contacts to other two-dimensional (2D) materials. However, a rise of electron temperature of the graphene under a current flow has not been seriously considered in many applications. Owing to its small electronic heat capacity and electron-phonon coupling, electron temperature of the graphene can be increased easily by the application of current. The heat generated within the graphene is transferred to the contacted 2D materials through the vdW interface and potentially influences their properties. Here, we compare the superconducting critical currents of an NbSe2 flake for two different methods of current application: with a Au/Ti electrode fabricated by thermal evaporation and with a graphene electrode contacted to the NbSe2 flake through a vdW interface. The influence of the heat transfer from the graphene to NbSe2 is detected through the change of the superconductivity of NbSe2. We found that the critical current of NbSe2 significantly reduces when the current is applied with the graphene electrode compared to that from the conventional Au/Ti electrode. Further, since the electron heating in graphene exhibits ambipolar back-gate modulation, we demonstrate the electric field modulation of the critical current in NbSe2 when the current is applied with graphene electrode. These results are attributed to the significant heat transfer from the graphene electrode to NbSe2 through vdW interface.