Observation of ultrahigh mobility surface states in a topological crystalline insulator by infrared spectroscopy
Topological crystalline insulators possess metallic surface states protected by crystalline symmetry, which are a versatile platform for exploring topological phenomena and potential applications. However, progress in this field has been hindered by the challenge to probe optical and transport prope...
| Main Authors: | , , , , , , , |
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| Other Authors: | |
| Format: | Article |
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Nature Publishing Group
2017
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| Online Access: | http://hdl.handle.net/1721.1/112715 https://orcid.org/0000-0001-8051-7349 https://orcid.org/0000-0002-8803-1017 |
| Summary: | Topological crystalline insulators possess metallic surface states protected by crystalline symmetry, which are a versatile platform for exploring topological phenomena and potential applications. However, progress in this field has been hindered by the challenge to probe optical and transport properties of the surface states owing to the presence of bulk carriers. Here, we report infrared reflectance measurements of a topological crystalline insulator, (001)-oriented Pb[subscript 1-x]Sn[subscript x]Se in zero and high magnetic fields. We demonstrate that the far-infrared conductivity is unexpectedly dominated by the surface states as a result of their unique band structure and the consequent small infrared penetration depth. Moreover, our experiments yield a surface mobility of 40,000 cm 2 V⁻¹s⁻¹ , which is one of the highest reported values in topological materials, suggesting the viability of surface-dominated conduction in thin topological crystalline insulator crystals. These findings pave the way for exploring many exotic transport and optical phenomena and applications predicted for topological crystalline insulators. |
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