砷化镓量子阱中动态核极化的门控

Gate control of dynamic nuclear polarization in GaAs quantum wells.

作者信息

Sanada H, Matsuzaka S, Morita K, Hu C Y, Ohno Y, Ohno H

机构信息

Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.

出版信息

Phys Rev Lett. 2005 Mar 11;94(9):097601. doi: 10.1103/PhysRevLett.94.097601. Epub 2005 Mar 8.

DOI:10.1103/PhysRevLett.94.097601

PMID:15783998

Abstract

Gate control of dynamic nuclear polarization under optical orientation is demonstrated in a Schottky-gated n-GaAs/AlGaAs (110) quantum well by time-resolved Kerr rotation measurements. Spin relaxation of electrons due to mechanisms other than the hyperfine interaction is effectively suppressed as the donor induced background electron density is reduced from metallic to insulating regimes. Subsequent accumulation of photoexcited electron spins dramatically enhances dynamic nuclear polarization at low magnetic field, allowing us to tune nuclear spin polarization by external gate voltages.

摘要

通过时间分辨克尔旋转测量，在肖特基栅控n型GaAs/AlGaAs（110）量子阱中证明了光取向条件下动态核极化的门控效应。随着施主诱导的背景电子密度从金属态降低到绝缘态，超精细相互作用以外的机制引起的电子自旋弛豫得到有效抑制。随后光激发电子自旋的积累在低磁场下显著增强了动态核极化，使我们能够通过外部栅极电压调节核自旋极化。