Heat transport in semiconductor crystals under large temperature gradients

摘要: We analyze and discuss the fundamental behavior of nonlocal/nonlinear contributions to heat transport by phonons in bulk cubic semiconductor (SC) crystals subject large temperature gradients. The calculation approach is based on solving steady-state Boltzmann-Peierls Transport Equation (BPTE) expanding phonon distribution function a series work out modeling within framework single relaxation time approximation using modified Debye-Callaway model which both longitudinal transverse modes are included explicitly. SC system treated as continuum, elastic, isotropic dispersionless medium. frequency dependences three-phonon anharmonic Normal Umklapp scattering processes kept same for all crystals. Our allows us obtain compact expressions first three thermal coefficients we limit our calculations. assume these be leading ones over whole range considered study. Their behaviors studied changing ambient temperature, Gruneisen parameters well mass-fluctuation parameter. In simplest case grey spectrum approximation, shed light very interesting result regarding expression effective conductivity κeff crystal when latter space-periodic profile that typically encountered Transient Thermal Grating (TTG) experiments. find an undoubtedly proves nonlocality nonlinearity sound robust explanation reduced measured was reported TTG