Enhancement in surface mobility and quantum transport of Bi2−xSbxTe3−ySey topological insulator by controlling the crystal growth conditions

• Published in: Scientific reports Vol. 8; no. 1; pp. 1 - 10
• Main Authors: Han, Kyu-Bum, Chong, Su Kong, Oliynyk, Anton O., Nagaoka, Akira, Petryk, Suzanne, Scarpulla, Michael A., Deshpande, Vikram V., Sparks, Taylor D.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 23.11.2018; Nature Publishing Group
• Subjects: 639/301/119/2792/4128; 639/301/119/2794; 639/301/930/1032; Crystal growth; Crystal structure; Growth conditions; Humanities and Social Sciences; Magnetic fields; Melting; Mobility; multidisciplinary; Science; Science (multidisciplinary); Melt Growth (MG); Surface Mobility; Bridgman Growth (BG); xSb xTe; Three-dimensional Topological Insulator
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-35674-z

Despite numerous studies on three-dimensional topological insulators (3D TIs), the controlled growth of high quality (bulk-insulating and high mobility) TIs remains a challenging subject. This study investigates the role of growth methods on the synthesis of single crystal stoichiometric BiSbTeSe 2 (BSTS). Three types of BSTS samples are prepared using three different methods, namely melting growth (MG), Bridgman growth (BG) and two-step melting-Bridgman growth (MBG). Our results show that the crystal quality of the BSTS depend strongly on the growth method. Crystal structure and composition analyses suggest a better homogeneity and highly-ordered crystal structure in BSTS grown by MBG method. This correlates well to sample electrical transport properties, where a substantial improvement in surface mobility is observed in MBG BSTS devices. The enhancement in crystal quality and mobility allow the observation of well-developed quantum Hall effect at low magnetic field.