The 3d transition metal dichalcogenide MX2 (M=Mn, Fe, Co, Ni, Cu, Zn; X=S, Se, Te) with pyrite structure has attracted widespread attention due to their novel physical properties. Among them, the CuX2 (X=S, Se, and Te) is the only known superconducting system, for which the superconducting transition temperatures (Tc) are 1.5 K (CuS2), 2.4 K (CuSe2) and 1.3 K (CuTe2), respectively. Because they can only be synthesized under high-pressure and high-temperature (HPHT) conditions, earlier reports on CuTe2 are based on the polycrystalline samples and the detailed physical properties have not been reported on single crystal so far. Here, we synthesized high-quality CuTe2 single crystals under HPHT conditions at 5 GPa and 900 ℃ using the Kawai type 6/8 two-stage multianvil apparatus and performed detailed crystal, transport, magnetism, and specific heat measurements on its physical properties. The results showed that it belongs to the weakly coupled type-Ⅱ superconductor with Tc about 1.3 K. We systematically compared the relevant superconducting parameters of CuS2, CuSe2, and CuTe2 and further revealed the relationship between their density of state near the Fermi surface and superconducting properties.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |