Quantum oscillations in the topological superconductor candidate Cu(0.25)Bi2Se3.

Quantum oscillations are generally studied to resolve the electronic structure of topological insulators. In Cu(0.25)Bi(2)Se(3), the prime candidate of topological superconductors, quantum oscillations are still not observed in magnetotransport measurement. However, using torque magnetometry, quantum oscillations (the de Haas-van Alphen effect) were observed in Cu(0.25)Bi(2)Se(3). The doping of Cu in Bi(2)Se(3) increases the carrier density and the effective mass without increasing the scattering rate or decreasing the mean free path. In addition, the Fermi velocity remains the same in Cu(0.25)Bi(2)Se(3) as that in Bi(2)Se(3). Our results imply that the insertion of Cu does not change the band structure and that conduction electrons in Cu doped Bi(2)Se(3) sit in the linear Dirac-like band.