Do Thi-Hong-Hai, Phan Van-Nham
Department of Physics, Hanoi University of Mining and Geology, Duc Thang, Bac Tu Liem, Hanoi, Vietnam.
Institute of Research and Development, Duy Tan University, 3 Quang Trung, Danang, Vietnam.
J Phys Condens Matter. 2022 Feb 23;34(16). doi: 10.1088/1361-648X/ac5199.
The excitonic condensate in semimetal and semiconducting materials with the assistance of the phonons in both the adiabatic and anti-adiabatic regimes has been investigated. In the framework of the random phase approximation, we analyse the static excitonic susceptibility function once the electrons and holes are described in the extended Falicov-Kimball model involving the electron-phonon interaction. The excitonic condensate transition point is detected as a divergence of the susceptibility function. The complex phase diagrams exhibit the significant impact of the adiabatic phonons on the stability of the excitonic condensation state. In contrast, phonons in the anti-adiabatic regime play a less role in the formation and the condensation of the excitons. Depending on the temperature or the external pressure, the excitonic condensate stability and its Bardeen-Cooper-Schrieffer-Bose-Einstein condensation crossover in the systems are also discussed in detail.
在绝热和反绝热两种情况下，借助声子对半金属和半导体材料中的激子凝聚进行了研究。在随机相位近似框架下，一旦在包含电子 - 声子相互作用的扩展法利科夫 - 金博尔模型中描述电子和空穴，我们就分析静态激子磁化率函数。激子凝聚转变点被检测为磁化率函数的发散点。复杂的相图展示了绝热声子对激子凝聚态稳定性的显著影响。相比之下，反绝热情况下的声子在激子的形成和凝聚中作用较小。还详细讨论了取决于温度或外部压力时，系统中激子凝聚的稳定性及其巴丁 - 库珀 - 施里弗 - 玻色 - 爱因斯坦凝聚交叉现象。
