Light-induced Shubnikov-de Haas oscillations and evidence of Dirac Fermions in n-type PbTe single quantum well

Abstract

In this work, we performed magnetotransport measurements in an n -type single quantum well (QW) grown by molecular beam epitaxy and found that, under illumination, the QW presents metallic behavior and Shubnikov-de Haas oscillations at low temperatures. Under dark conditions, the QW is an insulator and no quantum oscillations are observed. Several peaks were identified in the fast Fourier transform curves and some were addressed to the longitudinal and oblique valleys that compound the multiple-valley Fermi surface of PbTe. By investigating the Berry phases of the oscillation, a phase of ∼0.5, characteristic of Dirac Fermions , was obtained, in accordance with recent theoretical predictions of transport via topological surface states in PbTe films.