关键词: MoS2/
等离激元/
自旋-轨道耦合
English Abstract
Electron screening lengths and plasma spectrum in single layer MoS2
Tao Ze-Hua,Dong Hai-Ming
1.School of Physical Science and Technology, China University of Mining and Technology, Xuzhou 221116, China
Fund Project:Project supported by the Fundamental Research Funds for the Central Universities, China (Grant No. 2015XKMS077) and the National Natural Science Foundation of China (Grant No. 11604380).Received Date:08 July 2017
Accepted Date:07 September 2017
Published Online:05 December 2017
Abstract:We obtain the energy eigenvalues and wave functions of the single layer molybdenum disulfide by using an effective Hamiltonian. Moreover, the density of states and high electron-electron screening length up to 108 cm-1 are also evaluated based on the dielectric function of MoS2. It is shown that the quasi-linear energy bands split off due to the spin-orbit couplings. Plasmons in such a system are investigated theoretically within diagrammatic self-consistent field theory. In the random phase approximation, it is found that two plasma spectra can be produced via intra band transitions induced in conduction bands in monolayer MoS2 because of splitting off. The plasma spectrum frequency increases with increasing wave-vector q and electron density. It is found that the two plasmon modes induced by the spin intra-subband transitions are acoustic-like and depend strongly on wave-vector q. We find that the plasma spectrum is very different from those of graphene and two-dimensional electron gas due to the quasi-linear dispersion and spin-orbit couplings in single layer MoS2. Moreover, the plasmon frequency can be effectively controlled through changing the doping electron density. Our results exhibit some interesting features which can be utilized to realize the plasmonic devices based on the single layer MoS2.
Keywords: MoS2/
plasmon/
spin-orbit couplings
