Magnetotransport Measurements of the Surface States of Samarium Hexaboride using Corbino Structures

Autor: Zachary Fisk, Fan Yu, Tomoya Asaba, Gang Li, Colin Tinsman, Ziji Xiang, Steven Wolgast, Benjamin Lawson, Dae-Jeong Kim, Teoman Öztürk, Yun Suk Eo, Lu Li, Kai Sun, Cagliyan Kurdak, J. W. Allen
Přispěvatelé: Selçuk Üniversitesi
Jazyk: angličtina
Rok vydání: 2014
Předmět:
Zdroj: Wolgast, S; Eo, YS; Öztürk, T; Li, G; Xiang, Z; Tinsman, C; et al.(2015). Magnetotransport measurements of the surface states of samarium hexaboride using Corbino structures. Physical Review B-Condensed Matter and Materials Physics, 92(11). doi: 10.1103/PhysRevB.92.115110. UC Irvine: Retrieved from: http://www.escholarship.org/uc/item/3vc1b1nc
Popis: WOS: 000360601100001
The recent conjecture of a topologically protected surface state in SmB6 and the verification of robust surface conduction below 4 K have prompted a large effort to understand surface states. Conventional Hall transport measurements allowcurrent to flow on all surfaces of a topological insulator, so such measurements are influenced by contributions from multiple surfaces of varying transport character. Instead, we study magnetotransport of SmB6 using a Corbino geometry, which can directly measure the conductivity of a single, independent surface. Both (011) and (001) crystal surfaces show a strong negative magnetoresistance at all magnetic field angles measured. The (011) surface has a carrier mobility of 122 cm(2)/V.s with a carrier density of 2.5 x 10(13) cm(-2), which are significantly lower than indicated by Hall transport studies. This mobility value can explain the failure so far to observe Shubnikov-de Haas oscillations. Analysis of the angle dependence of conductivity on the (011) surface suggests a combination of a field-dependent enhancement of the carrier density and a suppression of Kondo scattering from native oxide layer magnetic moments as the likely origin of the negative magnetoresistance. Our results also reveal a hysteretic behavior whose magnitude depends on the magnetic field sweep rate and temperature. Although this feature becomes smaller when the field sweep is slower, it does not disappear or saturate during our slowest sweep-rate measurements, which is much slower than a typical magnetotransport trace. These observations cannot be explained by quantum interference corrections such as weak antilocalization but are more likely due to an extrinsic magnetic effect such as the magnetocaloric effect or glassy ordering.
National Science FoundationNational Science Foundation (NSF) [ECCS-1307744, DMR-1006500, DMR-1441965, DMR-0801253, DMR-1157490]; Department of EnergyUnited States Department of Energy (DOE) [DE-SC0008110]; Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK); China Scholarship CouncilChina Scholarship Council; National Basic Research Program of China (973 Program)National Basic Research Program of China [2012CB922002]; State of Florida; DOEUnited States Department of Energy (DOE)
We wish to acknowledge Kyunghoon Lee for his assistance with wirebonding the Corbino contacts, Juniar Lucien for polishing of crystal surfaces, and Jan Jaroszynski for discussion of the magnetocaloric effect. This work was supported by National Science Foundation Grant Nos. ECCS-1307744, DMR-1006500, DMR-1441965, and DMR-0801253, Department of Energy Award No. DE-SC0008110, the Scientific and Technological Research Council of Turkey (TUBITAK), the China Scholarship Council, and the National Basic Research Program of China (973 Program, Grant No. 2012CB922002). Device fabrication was performed in part at the Lurie Nanofabrication Facility, a member of the National Nanotechnology Infrastructure Network, which is supported by the National Science Foundation. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by National Science Foundation Cooperative Agreement No. DMR-1157490 and the State of Florida, and by the DOE.
Databáze: OpenAIRE
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