  Designing and searching for high lattice thermal conductivity materials in
both bulk and nanoscale level is highly demanding for electronics cooling.
Boron phosphide is a III-V compound semiconductor with superior structural and
thermal properties. In this work, we studied the lattice thermal conductivity
of hexagonal boron phosphide(h-BP) using first principles calculations. For
pure h-BP, we found a high lattice thermal conductivity (at 300K) of 561.2
Wm-1K-1 and 427.4 Wm-1K-1 along a-axis and c-axis respectively. These values
are almost equal to hexagonal silicon carbide(2H-SiC) and cubic boron
phosphide(c-BP). We also computed the length dependence thermal conductivity
for its applications in nanostructures. At nanoscale (L=100 nm), a high thermal
conductivity of ~71.5 Wm-1K-1(56.2 Wm-1K-1) is observed along a-axis(c-axis).
This result suggests that, h-BP will be a promising material for thermal
management applications in micro/nano electronics.

Materials Science;Mesoscale and Nanoscale Physics;Applied Physics;Atomic and Molecular Clusters;Computational Physics