Phonon spectrum and electronic structures of WTe2: a first-principles calculation

Abstract We investigate the electronic structures of intrinsic and doped WT e 2 by first-principles calculations based on the density functional theory. We first calculate the phonon dispersion and phonon density of states of WT e 2 . We found that all the phonon modes have positive energies, and that the optical phonon branches have high eigenvalues, which indicates that the structure of WT e 2 is thermodynamically stable. In the range of phonon energy from 0 to 10 meV, the acoustic and optical branches overlap, and thus there is no gap between them. The grouping of acoustic phonons and optical branches has implications for the thermal transport properties of WT e 2 . We next analyzed the electronic band structures of intrinsic and doped WT e 2 . We show that doping with other chalcogens in the same group of elements as Te reduces the energy band gap but leaves the overall band structure relatively unchanged. However, doping with elements from other groups, such as C and H, greatly modifies the electronic band structure, especially near the Fermi level. In fact, doping with such elements can elicit a transition of WT e 2 from a gapped to a gapless phase.