Band Structure of MoS2and NbS2

Recent Advancement on the Optical Properties of Two-Dimensional Molybdenum Disulfide (MoS2) Thin Films

“…The direct band-gap energies of EA and EB, as measured by different methods, are summarized in Table 1. Initially, the research was in agreement that the A and B exciton transitions occur at the Γ point [60][61][62]. There was some disagreement from M. R. Khan and G. J. Goldsmith's work in 1983, which put the A and B exciton transition at the A point of the Brillouin Zone [63].…”

Interactions and superconductivity in heavily doped MoS2

“…Theoretical first-principles-based calculations indicate a mass m eff of the order m eff ≈ 0.4 m 0 -1m 0 , [7][8][9][10][11]24,25,31 whereas early experimental measurements suggest m eff ranging from ∼0.01m 0 (Ref. 32) to ∼1m 0 .…”

“…[2][3][4] The existence of an energy gap makes MoS 2 a convenient material for nanoelectronics. 5,6 Metallic behavior can be induced, also as in graphene, by means of electric field effects or by doping, and the corresponding Fermi surface is typically made up of inequivalent Fermi pockets, [7][8][9][10][11][12] defining a valley degree of freedom which is strongly entangled with the spin degree of freedom, 13 and it can be further controlled and manipulated, opening promising perspectives for spintronics. At high carrier concentrations (n ∼ 10 14 cm −2 ), and in the presence of high-κ dielectrics, MoS 2 has also been shown to undergo a superconducting transition, with a doping-dependent critical temperature T c (n) which exhibits a maximum as a function of n and drops to zero at sufficiently large values of n. 14,15 A ferromagnetic behavior has also been reported in MoS 2 , [16][17][18][19] and it has been related to edges or to the existence of defects.…”

The thermal expansion of 2H-MoS2and 2H-WSe2between 10 and 320 K

“…These values of Ea are probably the thermal counterparts of the E± c direct optical energy gaps (77 K) which occur at 1.791 eV in MoS/ (Neville & Evans, 1976) and 1.782 eV in WSe2 (Bradley, Katayama & Evans, 1972). Energy gaps of this magnitude occur in the calculated band structures (Bromley, Murray & Yoffe, 1972;Harper & Edmondson, 1971;Huisman, de Jonge, Haas & Jellinek, 1971" Mattheiss, 1973Kasowski, 1973) but the transitions giving rise to the optical absorption have not been positively identified. The optical absorption edge in the 3R-MoS2 polytype occurs at a lower energy than in the 2H polytype (Clark & Williams, 1968).…”