论文标题
旋转双层石墨烯中的集体激发
Collective excitations in spin-polarized bilayer graphene
论文作者
论文摘要
我们计算自旋偏置BLG系统中等离子体振荡的等离子体频率和阻尼速率。使用用于动力学介电函数的长波长近似值，我们获得了等离子体频率的分析表达式，表明自旋极化P的程度对长波长等离子体频率的影响可忽略不计。数值计算表明，自旋极化的程度在小（大）波矢量下略微（强）等离子体频率略有影响，而阻尼速率的最大值随着P的增加而增加。我们还研究了载体密度和底物介电常数对不同偏振值不同值的等离激体性能的影响。数值计算出的临界波形，在该临界波形中，等离子体分散曲线撞击电子连续体的边缘，可随P减小，可用于实验确定自旋极化的程度。
We calculate the plasmon frequency and damping rate of plasma oscillations in a spin-polarized BLG system. Using the long wavelength approximation for dynamical dielectric function, we obtain an analytical expression for plasmon frequency showing that the degree of spin polarization P has negligible effect on the long wavelength plasmon frequency. Numerical calculations demonstrate that the degree of spin polarization affects slightly (strongly) plasmon frequency at small (large) wave-vectors and the maximum value of damping rate increases with increasing P. We also study the effects of carrier density and substrate dielectric constant on plasmon properties for different value of spin polarization. The numerically calculated critical wave-vector, at which the plasmon dispersion curve hits the edge of electron-hole continuum, decreases with P and can be used to determine experimentally the degree of spin polarization.
