摘要
结合第一性原理计算和动力学蒙特卡罗模拟研究了稀磁半导体(Ga,Mn)As中Mn杂质的沉积动力学规律。利用第一性原理计算和爬坡弹性带方法计算了Mn杂质的跃迁势垒和结合能,并把这些能量作为动力学蒙特卡罗模拟(Ga,Mn)As微观结构演化的输入数据。结果表明在外延生长退火下长时间的微观结构演化的背后机制是Ga空位调节Mn原子在Ga子晶格上进行扩散。这种扩散会导致Mn原子的聚集,进而降低了居里温度。此外,随着退火温度的升高Mn团簇聚集的速率也更快。在高温退火下容易导致相分离。
The combination of first-principles calculations and Kinetic Monte Carlo simulations is employed to study the precipitation dynamics of Mn dopants in diluted magnetic semiconductor（Ga,Mn）As.The migration barriers and binding energies of the Mn dopants were calculated by the first-principles and climbing image nudged elastic band method（CI-NEB）and being used as input data in Kinetic Monte Carlo simulations for microstructure evolution of（Ga,Mn）As.It is elucidated that the mechanism behind the long-term microstructure evolution during postgrowth annealing is the Ga vacancy mediated Mn diffusion on the Ga sublattice.This diffusion leads to Mn clustering,which reduces the Curie temperature.Furthermore,the clustering rate changes rapidly with the annealing temperature.The high-temperature annealing easily leads to a detectable phase separation.
出处
《材料导报》
EI
CAS
CSCD
北大核心
2015年第20期144-147,共4页
Materials Reports
基金
国家自然科学基金(61425004
11175066)
上海市科委(15×D1501500)
关键词
稀磁半导体
掺杂
动力学蒙特卡罗
diluted magnetic semiconductor
dopant
Kinetic Monte Carlo
