Topological Surface Transport Properties of Single-Crystalline SnTe Nanowire Muhammad Safdar, † Qisheng Wang, † Misbah Mirza, Zhenxing Wang, Kai Xu, and Jun He* National Center for Nanoscience and Technology, Beijing 100190, China * S Supporting Information ABSTRACT: SnTe has attracted worldwide interest since its theoretical predication as topological crystalline insulator. Because of promising applications of one-dimensional topo- logical insulator in nanoscale electronics and spintronics device, it is very important to realize the observation of topological surface states in one-dimensional SnTe. In this work, for the first time we successfully synthesized high-quality single crystalline SnTe nanowire via gold-catalyst chemical vapor deposition method. Systematical investigation of Aharonov- Bohm and Shubnikov-de Haas oscillations in single SnTe nanowire prove the existence of Dirac electrons. Further analysis of temperature-dependent Shubnikov-de Haas oscillations gives valuable information of cyclotron mass, mean-free path, and mobility of Dirac electrons in SnTe nanowire. Our study provides the experimental groundwork for research in low- dimensional topological crystalline insulator materials and paves the way for the application of SnTe nanowire in nanoelectronics and spintronics device. KEYWORDS: Single-crystalline SnTe nanowires, topological crystalline insulators, Aharonov-Bohm interference, Shubnikov-de Haas oscillations T opological insulators (TIs), an unusual quantum state of matter, are characterized by a gapless metallic surface state and insulating bulk gap. 1 On the surface of TIs, the electron spin is locked perpendicular to the momentum, which make the surface state of TIs immune to any time reversal perturbations such as nonmagnetic impurities and crystal defects. 2-4 These unique properties make TIs promising applications in novel spintronics and low-dissipation quantum computation. 5,6 In addition, TIs provides the basis of materials for realization of unique quantum mechanical effect such as quantum anomalous hall effect 7 and Majorana fermions. 5 The discovery of three-dimensional (3D) TIs protected by time-reversal symmetry 8 such as Bi 2 Te 3 , Sb 2 Te 3 , and Bi 2 Se 3 has simulated the search of new topological insulator protected by other symmetries. For example, topological crystalline insu- lators (TCIs), 9 a new topological state, are found to be protected by crystal symmetry. Among various materials, tin telluride (SnTe) with a rocksalt structure shows special mirror symmetry in face-centered cubic Brillouin zone. It has been predicted as the first distinctive type of TCIs where conductive surface states are expected on the highly symmetrical crystal surface of SnTe such as {001}, {110} and {111}. 10 Since the discovery of SnTe as remarkable TCIs, it has attracted worldwide interest and opens the gateway to the theoretical and experimental research of TCIs. Significantly, SnTe is a simple stoichiometric compound compared with other TCIs such as Pb 1-x Sn x Te, 11 which make it easier to be synthesized. Recently, Tanaka 12 et al. experimentally confirmed the existence of a metallic Dirac-cone surface state on the (001) surface of SnTe bulk crystals by angle-resolved photoemission spectra. However, very few magneto-transport measurements of TCIs SnTe, 13 a straightforward way to probe the surface topological states, have been reported presumably due to the dominant transport of bulk carriers from crystal defects and thermal excitations. 3 Compared with bulk counterparts, nanostructure TIs materials are highly competitive system for investigating the surface topological nature due to their large surface-to-volume ratio, 14-16 leading to an enhancement of contribution of topological surface carriers. In addition, nanostructures of TIs play a vital role for fundamental investigation of materials such as exotic surface states and spintronics applications. 17-19 As a result, it is of particular important to study the surface electronic state of TCI SnTe nanostructures by magneto- transport experiment. However, to the best of our knowledge, there is no experiment evidence showing the topological crystalline insulator nature of SnTe nanostructure. This may be due to the challenges in synthesis of high quality single crystalline low-dimensional SnTe nanosturctures. Here, we report for the first time the synthesis of highly single crystalline SnTe nanowire via gold-catalyst chemical vapor deposition (CVD) and the observation of topological Received: July 30, 2013 Revised: October 22, 2013 Published: October 31, 2013 Letter pubs.acs.org/NanoLett © 2013 American Chemical Society 5344 dx.doi.org/10.1021/nl402841x | Nano Lett. 2013, 13, 5344-5349