Non-Drude Magneto-Transport Behavior in a Topological Crystalline Insulator/Band Insulator Heterostructure

• Published in: Nano letters Vol. 18; no. 10; pp. 6538 - 6543
• Main Authors: Liu, Chieh-Wen, Wei, Feng, Premasiri, Kasun, Liu, Shuhao, Ma, Song, Zhang, Zhidong, Gao, Xuan P. A
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 10.10.2018
• Subjects: topological insulator; linear magneto-resistance; Drude model; Magneto-transport
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.8b03113

The Drude model is one of the most fundamental models used to understand the electronic carrier transport in materials, including recently discovered topological materials. Here, we present a magneto-transport study revealing the non-Drude transport behavior in a heterostructure of topological crystalline insulator (TCI) SnTe and band insulator PbTe which exhibits a nonsaturating linear magneto-resistance (MR) effect, a novel phenomenon widely observed in topological materials with gapless dispersion. It is shown that in the van der Pauw geometry in which the longitudinal and transverse magneto-resistances are measured to extract the magneto-conductivity, the two-band Drude model is not sufficient to self-consistently describe both the longitudinal and transverse magneto-conductivities. Furthermore, in the Corbino geometry, which directly measures the longitudinal magneto-conductivity σ xx (B) for a straightforward comparison with the Drude model, the MR, 1/σ xx (B), still reveals a large linear MR effect, in direct discrepancy with the Drude model. While shining further light on the multiple-carrier transport in TCI, this study highlights an unusual magneto-transport character of topological materials that challenges the standard Drude picture of electron transport.