Structural and electrical transport properties of Cu-doped Fe_{1 -x}Cu_xSe single crystals

We report the structural and electrical transport properties of Fe_{1 -x}Cu_xSe (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 Fe_{1 -x}Cu_xSe at x = 0.02 and 0.1, and reduces the sign-change temperature (T_R) of the Hall coefficient (R _H).