Pressure-Stabilized Tin Selenide Phase with an Unexpected Stoichiometry and a Predicted Superconducting State at Low Temperatures

Pressure‐Induced Metallization and Robust Superconductivity in Pristine 1T‐SnSe2

“…Around the critical point, the n e is enhanced to ≈10 19 cm −3 , concomitant with remarkable drop of resistance at 250 K from ≈100 Ω at ambient pressure to ≈1 Ω (see the inset of Figure 4). [26,27] However, the results of synchrotron XRD show the structure of 1T-SnSe 2 seems to be stable up to 46.0 GPa (see Figure 2). On the other hand, the superconducting onset transition temperature T c increases rapidly and remains a nearly constant value of ≈6.1 K between 30.1 and 50.3 GPa, which indicates the robust superconductivity under high pressure.…”

“…[28] Considering only the z position of the Se atoms is variable in this 1T structure, the standard Le Bail method was used for the refinement www.advelectronicmat.de via the general structure analysis system (GSAS) program. [26,27] One can see that upon compression from ambient pressure to 46.0 GPa, the parameter c and a decrease by ≈17.0% and 5.6%, respectively, revealing large anisotropy of axial compressibility due to the quasi-2D nature of the lattice. The refined lattice parameter a, c, and axis ratio c/a are displayed together in Figure 2b.…”

“…[23][24][25] The structural and physical properties of SnSe 2 under high pressure have been recently investigated by theoretical calculations, [26,27] while the experimental investigation is still lacking. [23][24][25] The structural and physical properties of SnSe 2 under high pressure have been recently investigated by theoretical calculations, [26,27] while the experimental investigation is still lacking.…”

“…[23][24][25] The structural and physical properties of SnSe 2 under high pressure have been recently investigated by theoretical calculations, [26,27] while the experimental investigation is still lacking. [26] In addition, Nguyen-Cong et al theoretically suggest that the hexagonal P-3m1 SnSe 2 phase is thermodynamically stable up to 18 GPa and experiences metallization above 8 GPa, concomitant with a similar decomposition at 30.0 GPa. [26] More interesting, the cubic I-43d Sn 3 Se 4 is not only a novel compound with an unexpected stoichiometry 3:4 but also predicted to be a superconductor at low temperatures, which has been synthesized in laser-heated diamond anvil cell.…”

“…[26], we performed high-pressure powder XRD measurements at room temperature. [26], we performed high-pressure powder XRD measurements at room temperature.…”