Spin-valley qubit in nanostructures of monolayer semiconductors: Optical   control and hyperfine interaction
  We investigate the optical control possibilities of spin-valley qubit carried by single electrons localized in nanostructures of monolayer TMDs, including small quantum dots formed by lateral heterojunction and charged impurities. The quantum controls are discussed when the confinement induces valley hybridization and when the valley hybridization is absent. We show that the bulk valley and spin optical selection rules can be inherited in different forms in the two scenarios, both of which allow the definition of spin-valley qubit with desired optical controllability. We also investigate nuclear spin induced decoherence and quantum control of electron-nuclear spin entanglement via intervalley terms of the hyperfine interaction. Optically controlled two-qubit operations in a single quantum dot are discussed. 
Yue Wu, Qingjun Tong, Gui-Bin Liu, Hongyi Yu, and Wang Yao
cond-mat.mes-hall cond-mat.mtrl-sci