Heat transport by Dirac fermions in normal/superconducting graphene junctions

We study heat transport in normal/superconducting graphene junctions. We find that while the thermal conductance displays the usual exponential dependence on temperature, reflecting the $s$-wave symmetry of the superconducting graphene, it exhibits an unusual oscillatory dependence on the potential height or the length of the barrier region. This oscillatory dependence stems from the emergent low-energy relativistic nature of fermions in graphene, essentially different from the result in conventional normal metal/superconductor junctions.

Figure 1

(Color online) The proposed experimental setup to measure heat transport by Dirac fermions in a graphene normal/superconductor proximity structure. The top and bottom gates allow for the chemical potential in the middle region to be adjusted.

Figure 2

(Color online) Thermal conductance as a function of $T∕T_C$ for various $k_{F}L$ with $U∕E_F=10$ and $E_F^{\prime }=100{\Delta }_0$ at $E_F=100{\Delta }_0$ in (a) and $E_F=10{\Delta }_0$ in (b).

Figure 3

(Color online) (a) Thermal conductance as a function of $U∕E_F$ for various $k_{F}L$ with $T∕T_C=0.5$ and $E_F=E_F^{\prime }=100{\Delta }_0$. (b) Thermal conductance as a function of $k_{F}L$ for various $U∕E_F$ with $T∕T_C=0.5$ and $E_F=E_F^{\prime }=100{\Delta }_0$.