Quantum oscillations and physical properties of LaCu2Si2

Abstract

High quality single crystals of LaCu2Si2 are successfully grown from a high temperature ternary melt. The physical properties are investigated by measurements of specific heat, electrical resistivity, thermoelectric power, and magnetization. The electrical resistivity follows an ordinary metallic behavior with a residual resistivity ρ0 = 0.87 μΩ cm and residual resistivity ratio (RRR) ρ(300 K)/ρ0 ∼ 13. Quantum oscillations for H || ab are clearly observed from electrical resistivity, magnetization, and thermoelectric power measurements in magnetic fields as low as 30 kOe and at temperatures as high as 20 K. In the earlier studies no quantum oscillations have been observed from both single crystal and polycrystalline samples. The small value of ρ0 and quantum oscillations indicate a high quality of LaCu2Si2 samples used in the present study. The cyclotron effective mass obtained from the analysis of the de Haas – van Alphen (dHvA) oscillations is small m0 ∼ 0.14me, which is consistent with the small electronic specific heat coefficient γ ∼ 3.4 mJ/mol K2. The detected dHvA frequencies of LaCu2Si2 are compared with those of the RCu2Si2 (R = Y, Th, and Ce) family.