Structural and electrical transport properties of Cu-doped Fe1–x Cu x Se single crystals* *Project supported by the National Key Research and Development of China (Grant No. 2018YFA0704200), the National Natural Science Foundation of China (Grant No. 11834016), and the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB25000000).

Abstract

We report the structural and electrical transport properties of Fe1–x Cu x Se (x = 0, 0.02, 0.05, 0.10) single crystals grown by a chemical vapor transport method. Substituting Cu for Fe suppresses both the nematicity and superconductivity of FeSe single crystal, and provokes a metal–insulator transition. Our Hall measurements show that the Cu substitution also changes an electron dominance at low temperature of un-doped FeSe to a hole dominance of Cu-doped Fe1–x Cu x Se at x = 0.02 and 0.1, and reduces the sign-change temperature (TR ) of the Hall coefficient (R H).