Spin-polarized Lasing in Quantum Dots

2014 Fiscal Year Final Research Report

• Project/Area Number: 22221007
• Research Category: Grant-in-Aid for Scientific Research (S)
• Allocation Type: Single-year Grants
• Research Field: Microdevices/Nanodevices
• Research Institution: Hokkaido University
• Principal Investigator: MURAYAMA Akihiro 北海道大学, 情報科学研究科, 教授 (00333906)
• Co-Investigator(Kenkyū-buntansha): SUEOKA Kazuhisa 北海道大学, 大学院情報科学研究科, 教授 (60250479)
• Co-Investigator(Renkei-kenkyūsha): SUGAWARA Hirotake 北海道大学, 大学院情報科学研究科, 准教授 (90241356)
• Project Period (FY): 2010-04-01 – 2015-03-31
• Keywords: ナノ構造作製 / 量子ドット / ナノ光デバイス / スピンデバイス / ナノ表面・界面

Outline of Final Research Achievements

We have studied spin-polarized lasing, which can transform electron-spin information into circular polarization properties in stimulated emission, by employing III-V compound semiconductor quantum dots (QDs) exhibiting strong suppression of spin relaxation.
Spin-injection dynamics and spin relaxation in QDs in addition to fabrication processes of QDs have been studied for the purpose of temporal spin storage during the emission. We show that Pauli spin blocking is a major factor of spin loss during the spin injection into QDs. To resolve this issue, we conclude that high density QDs and tunneling of spins from two-dimensional electron systems realize highly efficient and ultrafast spin injection into QDs. QD light emitting diodes with active layers composed of QDs and metallic ferromagnetic spin electrodes have been fabricated, which indicates circularly polarized electroluminescence reflecting efficient electron-spin injection.

Free Research Field

半導体量子ドット光スピントロニクス