2019/05/04 by Bumjoo Lee, Lee, Bumjoo, Jinsu Kim +25
Materials Science · Physics and Astronomy · #Chemical and Physical Properties of Materials #Electronic and Structural Properties of Oxides #FOS: Physical sciences #Graphene research and applications #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Topological Materials and Phenomena
paper · pdf · doi:10.48550/arxiv.1905.01429
openalex publication_date 2019/05/04 · openalex created_date 2022/07/29 · openalex updated_date 2026/07/28
High surface-mobility, which is attributable to topological protection, is a\ntrademark of three-dimensional topological insulators (3DTIs). Exploiting\nsurface-mobility indicates successful application of topological properties for\npractical purposes. However, the detection of the surface-mobility has been\nhindered by the inevitable bulk conduction. Even in the case of high-quality\ncrystals, the bulk state forms the dominant channel of the electrical current.\nTherefore, with electrical transport measurement, the surface-mobility can be\nresolved only below-micrometer-thick crystals. The evaluation of the\nsurface-mobility becomes more challenging at higher temperatures, where phonons\ncan play a role. Here, using spectroscopic techniques, we successfully\nevaluated the surface-mobility of Bi2Te3 (BT) at room temperature (RT). We\nacquired the effective masses and mean scattering times for both the surface\nand bulk states using angle-resolved photoemission and terahertz time-domain\nspectroscopy. We revealed a record-high surface-mobility for BT, exceeding\n33,000 cm2/(Vs) per surface sheet, despite intrinsic limitations by the\ncoexisting bulk state as well as phonons at RT. Our findings partially support\nthe interesting conclusion that the topological protection persists at RT. Our\napproach could be applicable to other topological materials possessing\nmultiband structures near the Fermi level.\n