Fermi surface topology and electronic transport properties of chiral crystal <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">NbGe</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> with strong electron-phonon interaction
Yoshiki J. Sato, Ai Nakamura, Rei Nishinakayama, R. OKAZAKI, Hisatomo Harima, Dai Aoki
Abstract
We report the electronic structures and transport properties of a chiral crystal ${\mathrm{NbGe}}_{2}$, which is a candidate for a coupled electron-phonon liquid. The electrical resistivity and thermoelectric power of ${\mathrm{NbGe}}_{2}$ exhibit clear differences compared to those of ${\mathrm{NbSi}}_{2}$ even though both niobium ditetrelides are isostructural and isoelectronic. We discuss the intriguing transport properties of ${\mathrm{NbGe}}_{2}$ based on a van Hove-type singularity in the density of states. The analysis of de Haas-van Alphen oscillations measured by the field modulation and magnetic torque methods reveals the detailed shape of the Fermi surface of ${\mathrm{NbGe}}_{2}$ by comparison with the results of energy band structure calculations using a local density approximation. The electron and hole Fermi surfaces of ${\mathrm{NbGe}}_{2}$ split into two because of the antisymmetric spin-orbit interaction. The temperature dependence of quantum oscillations indicates that the effective mass is isotropically enhanced in ${\mathrm{NbGe}}_{2}$ due to strong electron-phonon interaction.