Valley-selective circular dichroism of monolayer molybdenum disulphide

A two-dimensional honeycomb lattice harbours a pair of inequivalent valleys in the k-space electronic structure, in the vicinities of the vertices of a hexagonal Brillouin zone, K±. It is particularly appealing to exploit this emergent degree of freedom of charge carriers, in what is termed 'valleytronics'. The physics of valleys mimics that of spin, and will make possible devices, analogous to spintronics, such as valley filter and valve, and optoelectronic Hall devices, all very promising for next-generation electronics. The key challenge lies with achieving valley polarization, of which a convincing demonstration in a two-dimensional honeycomb structure remains evasive. Here we show, using first principles…

• NS
  National Science Foundation

  Awards: 91021007, 11174338
• UD
  U.S. Department of Energy

  Award: DE-FG03-02ER45958
• WF
  Welch Foundation

  Award: F-1255
• NN
  National Natural Science Foundation of China

  Awards: 91021007, 11174009, 11174338, 10874177, 10911130356, 10974238, 10934007
• NK
  National Key Research and Development Program of China

  Award: 2011CBA00109
• DO
  Division of Materials Sciences and Engineering