Temperature-driven evolution of critical points, interlayer coupling, and layer polarization in bilayer Mo S2

Luojun Du, Tingting Zhang, Mengzhou Liao, Guibin Liu, Shuopei Wang, Rui He, Zhipeng Ye, Hua Yu, Rong Yang, Dongxia Shi, Yugui Yao, Guangyu Zhang

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10 Scopus citations

Abstract

The recently emerging two-dimensional (2D) transition-metal dichalcogenides (TMDCs) have been a fertile ground for exploring abundant exotic physical properties. Critical points, the extrema or saddle points of electronic bands, are the cornerstone of condensed-matter physics and fundamentally determine the optical and transport phenomena of the TMDCs. However, for bilayer MoS2, a typical TMDC and the unprecedented electrically tunable venue for valleytronics, there has been a considerable controversy on its intrinsic electronic structure, especially for the conduction band-edge locations. Moreover, interlayer hopping and layer polarization in bilayer MoS2 which play vital roles in valley-spintronic applications have remained experimentally elusive. Here, we report the experimental observation of intrinsic critical points locations, interlayer hopping, layer-spin polarization, and their evolution with temperature in bilayer MoS2 by performing temperature-dependent photoluminescence. Our measurements confirm that the conduction-band minimum locates at the Kc instead of Qc, and the energy splitting between Qc and Kc redshifts with a descent of temperature. Furthermore, the interlayer hopping energy for holes and temperature-dependent layer polarization are quantitatively determined. Our observations are in good harmony with density-functional theory calculations.

Original languageEnglish
Article number165410
JournalPhysical Review B
Volume97
Issue number16
DOIs
StatePublished - Apr 9 2018

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    Du, L., Zhang, T., Liao, M., Liu, G., Wang, S., He, R., Ye, Z., Yu, H., Yang, R., Shi, D., Yao, Y., & Zhang, G. (2018). Temperature-driven evolution of critical points, interlayer coupling, and layer polarization in bilayer Mo S2. Physical Review B, 97(16), [165410]. https://doi.org/10.1103/PhysRevB.97.165410