Thermal conductivity transition regime of zigzag and armchair black phosphorus

The investigations of lattice thermal conductivity of few layer black phosphorus show the onset of anisotropic thermal conductivity cross-over between zigzag and armchair direction in the low temperature regime (~25K−40K). For the first time, we address anisotropic-isotropic-low anisotropic transition regimes of thermal conductivity in black phosphorus and discuss the influence of phonon-boundary, phonon-phonon and phonon-impurity scattering on transition regimes. Single set of phonon scattering coefficients for black phosphorus obtained are used to describe the thermal conductivity cross-over of zigzag and armchair black phosphorus. We analyze the thermal conductivity cross-over data and found to show the best fit to the recent experimental thermal conductivity reports in the wide temperature range (10K–600K). The importance of the phonon frequency and angle of phonon incidence dependent speculation reflections is discussed. © 2020 Elsevier B.V.