Thermal Conduction in Single-Layer Black Phosphorus: Highly Anisotropic?

摘要: The single-layer black phosphorus is characteristic for its puckered structure, which has leaded to highly anisotropy in optical, electronic, and mechanical properties. We report, using the non-equilibrium Green's function approach first-principles method, that thermal conduction very weak -- difference between two in-plane directions less than 4%. Our phonon calculations disclose acoustic branches have lower group velocities direction perpendicular pucker, as softer this direction, leading a weakening effect conductance direction. However, out-of-plane branch behaviors abnormally; i.e., velocity of higher although abnormal behavior closely related anisotropic Poisson's ratio phosphorus. As result counteraction modes mode, weaker parallel but pretty small.