Electrically tunable multiple Dirac cones in thin films of (LaO)2(SbSe2)2 family of materials

摘要

Two-dimensional Dirac physics has aroused great interests in condensed matterphysics ever since the discovery of graphene and topological insulators due toits importance in both fundamental physics and device applications. The abilityto control the properties of Dirac cones, such as bandgap and Fermi velocity,is essential for the occurrence of various new phenomena and the development ofnext-generation electronic devices. Based on first-principles calculations andan analytical effective model, we propose a new Dirac system with eight Diraccones in thin films of the (LaO)2(SbSe2)2 family of materials with an externalgate voltage. The advantage of this system lies in its tunability: theexistence of gapless Dirac cones, their positions, Fermi velocities andanisotropy all can be controlled by an experimentally feasible gate voltage. Weidentify the layer dependent spin texture induced by spin-orbit coupling as theunderlying physical reason for the tunability of Dirac cones in this system. Asa consequence, we show that the electrically tunable quantum anomalous Halleffect with a high Chern number can be induced by introducing magnetizationinto this system.