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arXiv 0912.0331cond-mat.mes-hall
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空穴Luttinger系统的波包动力学

Wave packet dynamics in hole Luttinger systems

V. Ya. Demikhovskii, G. M. Maksimova, E. V. Frolova

摘要:

对于有效自旋为3/2的空穴系统,我们用解析和数值方法分析了不同初始极化下波包的演化。这种系统的动力学由$4\times 4$ Luttinger哈密顿量确定。我们在“单粒子系统”的轻空穴态和重空穴态的任意叠加空间中工作。对于二维包,我们得到了波函数分量的解析解,并分析了概率密度和角动量密度的时空依赖性。根据参数$a=k_0d$的值($k_0$是平均动量矢量,而$d$是分组宽度),实现了两种演进方案。对于$a>>1$,初始波包分裂成两部分,并且包中心的坐标经历瞬态振荡或对于其它双频带系统的{ \it Zitterbewegung}(ZB)。在$a<<1$情况下,$t>0$处的概率密度分布几乎保持圆柱对称,波纹出现在波包的圆周上。在这种情况下,ZB不存在。我们评估和可视化的不同值的参数$a$的角动量密度的时空依赖性,具有多极结构。结果表明,由于轻重空穴态的干涉,在没有外磁场或有效磁场的情况下,平均动量分量可以进动。对于局域化的初始状态,这种进动具有瞬态特性。

英文摘要:

For hole systems with an effective spin 3/2 we analyzed analytically and numerically the evolution of wave packets with the different initial polarizations. The dynamics of such systems is determined by the $4\times 4$ Luttinger Hamiltonian. We work in the space of arbitrary superposition of light- and heavy-hole states of the "one-particle system". For 2D packets we obtained the analytical solution for the components of wave function and analyzed the space-time dependence of probability densities as well as angular momentum densities. Depending on the value of the parameter $a=k_0d$ ($k_0$ is the average momentum vector and $d$ is the packet width) two scenarios of evolution are realized. For $a>>1$ the initial wave packet splits into two parts and the coordinates of packet center experience the transient oscillations or {\it Zitterbewegung} (ZB) as for other two-band systems. In the case when $a<<1$ the distribution of probability density at $t>0$ remains almost cylindrically symmetric and the ripples arise at the circumference of wave packet. The ZB in this case is absent. We evaluated and visualized for different values of parameter $a$ the space-time dependence of angular momentum densities, which have the multipole structure. It was shown that the average momentum components can precess in the absence of external or effective magnetic fields due to the interference of the light- and heavy hole states. For localized initial states this precession has a transient character.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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