Signatures of Dynamic Screening in Interfacial Thermal Transport of Graphene

The interaction between graphene and various substrates plays an important and limiting role on the behavior of graphene films and devices. Here we uncover that dynamic screening of so-called remote substrate phonons (RPs) has a significant effect on the thermal coupling at the graphene-substrate interface. We calculate the thermal conductance hRP between graphene electrons and substrate, and its dependence on carrier density and temperature for SiO₂, HfO₂, h-BN, and Al₂O₃ substrates. The dynamic screening of RPs leads to one order of magnitude or more decrease in hRP and a change in its dependence on carrier density. Dynamic screening predicts a decrease of ~1 MW K⁻¹ m⁻² while static screening predicts a rise of ~10 MW K⁻¹ m⁻² when the carrier density in Al₂O₃-supported graphene is increased from 10¹² to 10¹³ cm⁻².