Study of photo-induced electron spin transfer with time-resolved micro Kerr rotation measurement under low temperature and high magnetic field

2014 Fiscal Year Final Research Report

• Project/Area Number: 24540315
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics I
• Research Institution: Chiba University
• Principal Investigator: MINO Hirofumi 千葉大学, 普遍教育センター, 准教授 (40323430)
• Co-Investigator(Renkei-kenkyūsha): OTO Kenichi 千葉大学, 理学研究科, 教授 (30263198) ; TSUCHIYA Takuma 北海道大学, 工学研究科, 准教授 (40262597)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 光誘起スピン偏極 / スピンイメージング / 半導体量子井戸 / スピン緩和 / 光電流

Outline of Final Research Achievements

To observe the spatial and temporal behavior of photo-created electron spins, we developed pump-probe micro-Kerr rotation measurement system, which has 1μm spatial resolution, 100μm x 100μm scanning region, high sensitivity spin detection under several μW laser excitation. Photocurrent measurements were also made possible in this system. In ZnSe/BeTe quantum wells, not only the Dresselhaus effect but also another effect is found to be necessary to explain the anisotropic spin propagation. In CdMnTe quantum wells the suppression of the photo-induced exciton spin precession, which means the effective g-factor is zero, was observed at critical temperature. This result was well explained by the competition between the exciton Zeeman effect and exciton-Mn exchange interaction. The spin lifetime indicated intensive increase above the critical temperature. In (BEDT-TTF)(TCNQ) crystals the suppression of photogenerated carrier conduction was observed below the antiferromagnetic transition.

Free Research Field

半導体光物性