Itinerant 5f Electrons and the Fermi Surface Properties in an Enhanced Pauli Paramagnet NpGe₃

Abstract

We succeeded in growing a high-quality single crystal of an enhanced Pauli paramagnet, NpGe₃, by the Bi-flux method, and observed the de Haas–van Alphen (dHvA) effect. The topology of a Fermi surface is well explained by the relativistic linear augmented-plane-wave (LAPW) band calculations based on the 5f itinerant band model. The Fermi surface consists of a nearly spherical electron-Fermi surface with necks along the ⟨100⟩ direction, forming a hollow ball, centered at the R point, which is derived from the single band. The cyclotron effective mass is in the range from 2.6 to 16m₀, which is enhanced approximately 3.5 times from the corresponding band mass.