Electronic, optical, and vibrational properties of BNH from first-principles calculations.

The structural, electronic, optical, and vibrational properties of BNH have been calculated by means of the first-principles density functional theory (DFT) calculations within the generalized gradient approximation (GGA) and the local density approximation (LDA). The calculated structural parameters of BNH are in good agreement with experimental data. The obtained band structure of BNH shows that it has an indirect band gap with 5.007 eV, indicating that it presents insulation characteristic. The total and partial density of states (DOS) of BNH are given, which tell us the states of the orbital occupation. With the band structure and density of states, we have analyzed the optical properties including the complex dielectric function, refractive index, absorption, conductivity, loss function, and reflectivity. By the contrast, it is found that optical anisotropy is observed in the (001) direction and (100) direction. Moreover, the vibrational properties have been obtained and analyzed, showing that BNH is dynamically stable due to that there is no imaginary frequency. The frequencies associating with the vibrations are given, which show that BNH has a low mechanical modulus and thermal conductivity.