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.

在这项工作中，我们在通过分子束外延生长的n型单量子阱(QW) 中进行了磁输运测量，发现在光照下，QW 在低温下呈现金属行为和 Shubnikov-de Haas 振荡。在黑暗条件下，QW 是绝缘体，没有观察到量子振荡。在快速傅里叶变换曲线中确定了几个峰，一些峰被定位到纵向和斜谷，它们复合了 PbTe 的多谷费米表面。根据最近通过 PbTe 薄膜中拓扑表面态传输的理论预测，通过研究振荡的贝里相位，获得了狄拉克费米子特征的 ~0.5 相位。