Communications in Theoretical Physics
In the weakly coupled electron-phonon systems, the existing theory pointed out that the energy spectra of polaron include four electronic bound states. Our work shows that, due to the non-nearest neighbor hopping interactions, the electron-hole symmetry of the energy band structure implied by SSH model is broken, and the numbers of the bound electronic states are changed. For a negative charged polaron, one new bound state is found near the bottom of conduction band, and the original two bound states below the bottom of the valence band and above the top of the conduction band disappear. For a positive charged polaron, five bound states have been found: one of them is an additional bound state at the top of the conduction band, the others are just the states found in the SSH model. Besides, the energy gap 2 Delta is slightly shifted by turning on the long-range hopping interactions.
关键词:
soliton
郝晓飞
,
禹定臣
,
郝东山
量子电子学报
doi:10.3969/j.issn.1007-5461.2010.02.021
应用多光子非线性Compton散射模型和耦合非线性薛定谔方程,研究了Compton散射下光折变晶体中的孤子传输特性,结果表明,光折变晶体热透镜效应的实质,是晶体内形成的光孤子与空间电荷场中的孤子传输与耦合的过程,其耦合特性不仅与两波导中的孤子的相对相位有关,而且与Compton散射有关.两波导中的孤子的相对相位相同或相反,散射都会使它们之间发生能量交换和交换能量的周期发生变化,从而使形成的孤子的轮廓变得模糊.即使光沿着晶体的光轴方向传输,也有发生双折射的可能性.
关键词:
光通信
,
光折变晶体
,
热透镜效应
,
孤子
,
耦合
,
多光子非线性Compton散射
