圆柱形量子线中的极化子效应

The polaron effect in a cylindrical quantum wire

分别采用LLP变分方法和微扰方法研究了圆柱形自由量子线的极化子效应 ,在计算中考虑了类体纵光学声子模及表面声子模的贡献 .结果显示表面声子模在量子线半径较小时产生强烈的极化子效应 ,而类体模的贡献则随量子线半径的增加逐渐趋于三维体材料的结果 .分析还发现 ,对于量子线、量子点等强受限体系 ,微扰方法得到的结果较LLP变分方法的结果合理 .

The LLP variational approach and the perturbation method are employed to study the polaron effect in a freestanding quantum wire, both the contribution from the bulk-like longitudinal optical phonon modes as well as the surface optical phonon modes are taken into consideration. Result showed that the surface phonon modes can cause strong polaron effect for small wire radius. While the contribution of the LO phonon modes increases gradually as the radius increases and finally reaches the three dimensional limit,which agrees with the bulk polaron. Analysis also shows that the perturbation method is better in dealing with the polaron problem in the strongly confining systems such as quantum wires and quantum dots.