室温下(Ga,Mn)As中载流子的自旋弛豫特性  

Carrier spin relaxation in (Ga,Mn)As at room temperature

作　　者：刘晓东[1] 王玮竹[2] 高瑞鑫[1] 赵建华[2] 文锦辉[1] 林位株[1] 赖天树[1] 

机构地区：[1]中山大学物理系,光电材料与技术国家重点实验室,广州510275 [2]中国科学院半导体研究所半导体超晶格国家重点实验室,北京100083

出　　处：《物理学报》2008年第6期3857-3861,共5页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:60490295,60678009,10334030);高等学校博士学科点专项科研基金(批准号:20050558030)资助的课题~~

摘　　要：运用飞秒时间分辨抽运-探测克尔光谱技术,研究了室温下退火及未退火(Ga,Mn)As的载流子自旋弛豫的激发能量密度依赖性,发现电子自旋弛豫时间随激发能量密度增加而增大,而在同一激发能量密度下,退火样品比未退火样品具有更短的载流子复合时间、电子自旋弛豫时间和更大的克尔转角,显示DP机理是室温下(Ga,Mn)As的电子自旋弛豫的主导机理.退火(Ga,Mn)As的超快克尔增强效应显示其在超高速全光自旋开关方面的潜在应用价值,也为(Ga,Mn)As铁磁性起源的p-d交换机理提供了证据.In this paper, the excitation energy density dependence of carrier spin relaxation is studied at room temperature for the as-grown and annealed （Ga,Mn）As samples using femtosecond time-resolved pump-probe Kerr spectroscopy. It is found that spin relaxation lifetime of electrons lengthens with increasing excitation energy density for both samples, and the annealed （Ga,Mn）As has shorter carrier recombination and electron spin relaxation lifetimes as well as larger Kerr rotation angle than the as-grown （Ga,Mn）As under the same excitation condition, which shows that DP mechanism is dominant in the spin relaxation process for （Ga,Mn）As at room temperature. The enhanced ultrafast Kerr effect in the annealed （Ga,Mn）As shows the potential application of the annealed （Ga,Mn）As in ultrafast all-optical spin switches, and also provides a further evidence for the p-d exchange mechanism of the ferromagnetic origin of （Ga,Mn）As.

关 键 词：(Ga Mn)As稀磁半导体 时间分辨克尔光谱 电子自旋弛豫 DP机理 

分 类 号：O482[理学—固体物理]