Superconductivity in Pristine 2Ha-MoS2 at Ultrahigh Pressure

As a follow-up of our previous work on pressure-induced metallization of the 2H(c)-MoS2 [Chi et al., Phys. Rev. Lett. 113, 036802 (2014)], here we extend pressure beyond the megabar range to seek after superconductivity via electrical transport measurements. We found that superconductivity emerges in the 2H(a)-MoS2 with an onset critical temperature T-c of ca. 3 K at ca. 90 GPa. Upon further increasing the pressure, Tc is rapidly enhanced beyond 10 K and stabilized at ca. 12 K over a wide pressure range up to 220 GPa. Synchrotron x-ray diffraction measurements evidenced no further structural phase transition, decomposition, and amorphization up to 155 GPa, implying an intrinsic superconductivity in the 2H(a)-MoS2. DFT calculations suggest that the emergence of pressure-induced superconductivity is intimately linked to the emergence of a new flat Fermi pocket in the electronic structure. Our finding represents an alternative strategy for achieving superconductivity in 2H-MoS2 in addition to chemical intercalation and electrostatic gating.