Lattice thermal conductivity of topological insulator BiSe nanocrystals: comparison from theoretical and experimental.

Lattice thermal conductivity () calculations using the Wiedemann-Franz law involve electrical conductivity, which introduces an error in the actual value of . We have adopted a non-contact measurement technique and calculated the from the temperature and power-dependent Raman spectra of the BiSe nanocrystals with truncated hexagon plate morphology stabilized in a hexagonal crystal structure. The hexagon plates of BiSe are 37 to 55 nm thick with lateral dimensions around 550 nm.

The effect of mechanical strain on the Dirac surface states in the (0001) surface and the cohesive energy of the topological insulator BiSe.

The band gap ( ) engineering and Dirac point tuning of the (0001) surface of 8 QLs (quintuple layers) thick BiSe slab are explored using the first-principles density functional theory calculations by varying the strain. The strain on the BiSe slab primarily varies the bandwidth, modifies the p - orbital population of Bi and moves the Dirac point of the (0001) surface of BiSe. The Dirac cone feature of the (0001) surface of BiSe is preserved for the entire range of the biaxial strain.