Role of Se vacancies on Shubnikov-de Haas oscillations in Bi2Se3: A combined magneto-resistance and positron annihilation study
Materials Science Group, Indira Gandhi Centre for Atomic Research - Kalpakkam-603102, Tamil Nadu, India
Received: 26 September 2014
Accepted: 2 December 2014
Magneto-resistance measurements coupled with positron lifetime measurements, to characterize the vacancy-type defects, have been carried out on the topological insulator (TI) system Bi2Se3 of varying Se/Bi ratio. Pronounced Shubnikov-de Haas (SdH) oscillations are seen in nominal Bi2Se3.1 crystals for measurements performed in magnetic fields up to 15 T in the 4 K–10 K temperature range, with field applied perpendicularly to the (001) plane of the crystal. The quantum oscillations, characteristic of 2D electronic structure, are seen only in the crystals that have a lower concentration of Se vacancies, as inferred from positron annihilation spectroscopy.
PACS: 72.80.Vp – Electronic transport in graphene / 72.15.Gd – Galvanomagnetic and other magnetotransport effects / 78.70.Bj – Positron annihilation
© EPLA, 2014