133 / 2023-04-14 16:23:47

Transport properties of single-crystalline Cu0.02TiSe2

高压物理与材料科学 > 功能材料-海报

Charge density waves (CDWs) states often appear in low-dimensional electronic systems, which are periodic modulations of the density of conducting electrons in solids. Layered dichalcogenides provide the most well-studied examples, among which TiSe₂ was one of the first discovered CDW-bearing materials. It has been found that as Cu is doped into TiSe₂ to form Cu_xTiSe₂, the CDW transition is continuously suppressed with increasing Cu doping concentration, and a new superconducting state appears around x = 0.04^[1]. Here we investigate the evolution of resistance, magnetoresistance, and Hall resistance of single-crystal samples of Cu_xTiSe₂ at different temperatures and pressures for doping concentrations of x = 0.02. It can be seen that Cu_0.02TiSe undergoes a CDW phase transition near 155 K as temperature decreases, but the sign of the Hall coefficient remains negative. Meanwhile, negative magnetoresistance appears at low temperatures. As pressure increases, the CDW is gradually completely suppressed and the energy bands are dominated by electron-type carriers before the collapse of the CDW phase transition and reverse into the hole-type one after the collapse of CDW. Meanwhile, the sign of the Hall coefficient changes from negative to positive.