Research Article Open Access
Charge transport in Weyl 2D materials
Halina Grushevskaya, George Krylov*
Faculty of Physics, Belarusian State University, 4 Nezaleznasti ave., Minsk, 220030, Belarus
Adv. Mater. Proc., 2018, 3 (2), 68-74
Publication Date (Web):05 February 2018
Copyright © IAAM-VBRI Press
Earlier proposed theoretical approach to the band theory of two-dimensional (2D) semimetals based on a self-consistent Dirac–Hartree–Fock field approximation, a quasi-relativistic model of Dirac 2D material in the tight-binding approximation with accounting of p-electron orbitals has been developed. Fermi velocity becomes an operator within this approach. The model admits a Weyl type of charge carriers described by chiral bispinors. Since Weyl fermions in a pair have equal in absolute but opposite in sign values of pseudo- helicity (topological charge), due to the topological charge conservation law Weyl fermions can decay only in pairs. Therefore, in contrast to the Dirac electrons and holes, Weyl fermions turns out to be long-lived quasiparticles. Stability of the band structure of the 2D materials is stipulated by coupling of valley currents with pseudospins of chiral Weyl charge carriers. Numerical simulation of the band structure has been performed for the atomically thin model layers (monolayers) of C and Pb atoms, taking into account only corrections up to 4th order in wave vector. Such features of the band structure of 2D semimetals as appearance of three pairs of Weyl-like nodes; partial removal of Dirac cone and replicas degeneration are shown to be naturally explained within the developed formalism. Since the Dirac cone replica is split into oppositely directed cones, the monolayers of atoms C and Pb are 2D materials, in which pairs of Weyl massless fermions can be excited. Simulation of charge transport in these materials has been performed. Copyright © 2018 VBRI Press.