Quantum Electrical Transport in Topological Insulator Nanowires

Sep. 02(Fri) 4:00 PM, E6-2(1st fl) #1323
Dr. Yong-Joo Doh, Department of Physics and Photon Science, GIST

Abstract:
Single-crystalline nanostructures of β-Ag2Se and Bi2Se3, three-dimensional(3D) topological insulators (TIs), were synthesized using the chemical vapor transport method. The topological surface states were verified by measuring electronic transport properties such as the weak antilocalization effect, Aharonov-Bohm oscillations, and Shubnikov-de Haas oscillations.[1,2] The band inversion in β-Ag2Se is attributed to a strong spin-orbit coupling and Ag-Se bonding hybridization. The superconducting junctions of β-Ag2Se nanostructures were also made using superconducting Al electrodes.[3] Very large supercurrent in the junction enables us to observe the macroscopic quantum tunneling behavior in the narrow junction limit, which is in contrary to the PbS-nanowire-based superconducting junctions[4]. Our observations would provide new meaningful information about 3D TIs, which could be useful for spintronics and superconducting quantum information devices applications.

1. J. Kim, A. Hwang, S.-H. Lee, S.-H. Jhi, S. Lee, Y. C. Park, S.-I Kim, H.-S. Kim, Y.-J. Doh*, J. Kim*, B. Kim*, ACS Nano (2016) 10, 3936.
2. H.-S. Kim, N.-H. Kim, Y. Yang, X. Peng, D. Yu, Y.-J. Doh*, (in preparation)
3. J. Kim, B.-K. Kim, H.-S. Kim, B. Kim*, Y.-J. Doh*, (in preparation).
4. B.-K. Kim, H.-S. Kim, Y. Yang, X. Peng, D. Yu, Y.-J. Doh*, ArXiv:1607.07151 (submitted).

Contact: Sung Jae Cho, Physics Dept., (sungjae.cho@kaist.ac.kr)