Theoretical Study of Spin-related Phenomena with Topological Invariants and Design of Its Application Devices

2014 Fiscal Year Final Research Report

• Project/Area Number: 24560001
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Applied materials science/Crystal engineering
• Research Institution: Hokkaido University
• Principal Investigator: KONDO Kenji 北海道大学, 電子科学研究所, 准教授 (50360946)
• Co-Investigator(Kenkyū-buntansha): KAIJU Hideo 北海道大学, 電子科学研究所, 准教授 (70396323)
• Co-Investigator(Renkei-kenkyūsha): SASAKURA Hirotaka 北海道大学, 電子科学研究所, 助教 (90374595)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: スピントロニクス / 物性理論 / 第一原理計算 / 磁性 / スピン輸送

Outline of Final Research Achievements

We have proposed a novel device which is called "spin quantum cross structure device (SQCS-device)". In this study, the spin conductance was calculated for a SQCS-device having a topological insulator as the left electrode and a normal metal as the right electrode. Topological insulators have attracted much interest by the exotic character that they have insulating bulk states and conducting surface states simultaneously. Their band structures are determined by time reversal symmetry. Therefore, we introduced a magnetic insulator deposited on the topological insulator to control its band structure in the model. Then, the spin conductance was calculated as a function of magnetization of the magnetic insulator for the SQCS-device with the topological insulator. As a result, it is found that the magnetization of the magnetic insulator can control the spin conductance very well. This result suggests that the SQCS-device with the topological insulator can be a promising novel device.

Free Research Field

応用物理学および工学