Non-Markovian spin transfer dynamics in magnetic semiconductors despite short memory times
Non-Markovian spin transfer dynamics in magnetic semiconductors despite short memory times
复制标题
尽管存储时间短，磁性半导体中的非马尔可夫自旋转移动力学
DOI：
10.1103/physrevb.87.205301
复制
发表时间：
2013
影响因子：
3.7
通讯作者：
T. Kuhn
中科院分区：
文献类型：
--
作者：
C. Thurn;M. Cygorek;V. M. Axt;T. Kuhn
提出了掺锰稀磁半导体中载流子与锰原子之间自旋转移的量子动力学理论。事实证明，与这些过程相关的典型记忆时间比自旋转移的时间短几个数量级。然而，通过忽略记忆而得到的马尔可夫速率方程只适用于大体积体系。对于量子阱和量子线，量子动力学结果在一定条件下定性地偏离了马尔可夫极限。不同于最初制备的过剩电子自旋的单调衰变，发现了过冲甚至相干振荡。结果表明，这些特征是由于能量-时间不确定引起的载流子能量再分布引起的。
A quantum kinetic theory of the spin transfer between carriers and Mn atoms in a Mn doped diluted magnetic semiconductor is presented. It turns out that the typical memory time associated with these processes is orders of magnitude shorter than the time scale of the spin transfer. Nevertheless, Markovian rate equations, which are obtained by neglecting the memory, work well only for bulk systems. For quantum wells and wires the quantum kinetic results qualitatively deviate from the Markovian limit under certain conditions. Instead of a monotonic decay of an initially prepared excess electron spin, an overshoot or even coherent oscillations are found. It is demonstrated that these features are caused by energetic redistributions of the carriers due to the energy-time uncertainty.