Fermi surface and mass enhancement in the topological nodal-line semimetal NaAlSi

Quantum oscillations in the magnetic torque for the topological nodal-line semimetal NaAlSi with a superconducting transition at Tc = 7 K have been measured to investigate the Fermi surface. Four oscillation branches, ??, ??, ?? , and ?? are observed, whose frequency ranges from 40 to 380 T in magnetic fields parallel to the c axis. The results are consistent with the present first-principles band calculations, showing the presence of small Fermi surfaces elongated in the kz direction. We obtain the large mass enhancement factors 2.0 for ?? and 3.1 for ?? , ascribed to many-body effects likely responsible for the superconductivity. A nontrivial Berry phase is obtained for ??, arising from the linear dispersion of the energy band.

Automated summary

Quantum oscillations in magnetic torque have been measured to investigate the Fermi surface of the topological nodal-line semimetal NaAlSi with a superconducting transition. The results show the presence of small Fermi surfaces elongated in the kz direction and four oscillation branches. Large mass enhancement factors have been obtained, likely associated with superconductivity.