Hydrodynamic signatures in thermal transport in devices based on two-dimensional materials: An <i>ab initio</i> study

We investigate the features arising from hydrodynamic effects in graphene and phosphorene devices with finite heat sources, using ab initio calculations to go beyond Callaway's model inform a full linearized scattering operator, solving phonon Boltzmann transport equation through energy-based deviational Monte Carlo methods. explain mechanisms that create those features, showing boundary relation of sample dimensions nonlocal length $\ensuremath{\ell}$ are determinant factors, regardless relative importance normal versus resistive scattering. From this point view, reflects ability randomize flux, we show approximations made on operator may have, value $\ensuremath{\ell}$, qualitative consequences signatures behavior.