de Haas–van Alphen Effect and Fermi Surface Properties in Single-Crystalline ThCu₂Si₂

We succeeded in growing high-quality single crystals of ThCu₂Si₂ with the ThCr₂Si₂-type tetragonal structure by the Sn-flux method and measured the electrical resistivity, specific heat, and de Haas–van Alphen (dHvA) effect to study the Fermi surface properties. Comparing this experiment results with those of the full-potential LAPW band calculation, we found that the detected main dHvA branches named α, αA, γ1, and γ₂ correspond to two-hole Fermi surfaces, while branches β and βA correspond to an electron Fermi surface centered at the Γ point in the Brillouin zone. The detected dHvA branches are well explained by the results of the band calculations. The detected cyclotron effective masses are in the range from 0.25 to 1.02m₀, where m₀ is the rest mass of an electron. The obtained Fermi surfaces of ThCu₂Si₂ are compared with those of the heavy-fermion superconductor CeCu₂Si₂ from the viewpoint of the Fermi surface properties.