上海科技大学知识管理系统

For the nanoscale structures, disorder scattering plays a vital role in the carriers’ transport, including electrons
and high-frequency phonons. The capability for effectively treating the disorders, including both diagonal and
off-diagonal disorders, is indispensable for quantum transport simulation of realistic device materials. In this
work, we report a self-consistent nonequilibrium mean-field quantum transport approach, by combining the
auxiliary coherent potential approximation (ACPA) and nonequilibrium Green’s function method, for calculating
the phonon transport through disordered material structures with the force-constant disorders (including the
Anderson-type disorder). The nonequilibrium vertex correction (NVC) is derived in an extended local degree of
freedom to account for both the multiple disorder scattering by force-constant disorder and the nonequilibrium
quantum statistics. We have tested the ACPA-NVC method with the fluctuation-dissipation theorem at the
equilibrium and obtained very good agreement with supercell calculations for the phonon transmission. To
demonstrate the applicability, we apply ACPA-NVC to calculate the thermal conductance for the disordered
Ni/Pt interface, and important effects of force-constant disorder are revealed. ACPA-NVC method provides
an effective quantum transport approach for simulating disordered nanoscale devices, and the generalization to
simulate disordered nanoelectronic device is straightforward.