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Nonreciprocal Giant Magneto-Optic Effects in Transition-Metal Dichalcogenides without Magnetic Field
Haixia Da1,2, Lei Gao1,2, Weiqiang Ding3
1College of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications , Nanjing, Jiangsu 210046, China.
Abstract:
Magnetic exchange field has been demonstrated to be effective in enhancing the valley splitting of monolayer transition-metal dichalcogenides experimentally. However, how magnetic exchange coupling affects the magnetooptical behaviors in massive Dirac systems remains elusive. Using k⃗·p⃗ model and Kubo formula, we theoretically report that optical Hall conductivity and giant magnetooptical effects can be induced in monolayer transition-metal dichalcogenides even if there is no any magnetic field involved when considering magnetic exchange interaction. Such an unusual result originates from the fact that the existence of magnetic exchange coupling effectively enables the breaking of time reversal symmetry, which grants the removal of valley degeneracy and unveils the possibility of generation and manipulation of magnetooptical effects in monolayer transition-metal dichalcogenides with no need for magnetic field. Our results suggest that the presence of magnetic exchange coupling of transition-metal dichalcogenides represents an alternative strategy capable of inducing magnetoopitcal effects, which can be extended to other monolayer massive Dirac systems.
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