AI 中文总结
研究泵浦激子系统的TR-ARPES，基于DPOA理论框架，考虑库仑相互作用，分析平衡与非平衡状态下的相图及边带情况，证实相关实验观察，确立DPOA为模拟相互作用电子系统超快现象的有效准确方法。
AI 中文摘要
我们基于动态投影算符方法（DPOA）开发了一个理论框架，用于研究泵浦激子系统的时间分辨角分辨光电子能谱（TR-ARPES）。该形式体系在哈特里-福克（HF）水平上包含库仑电子-电子相互作用，能捕捉泵浦脉冲作用下激子束缚态的形成。以二维双带半导体为例分析平衡相图，发现随着库仑相互作用强度或范围增加，会从半导体相转变为激子绝缘相。非平衡时，当泵浦频率与激子模式共振，泵浦脉冲消失后激子序参量的相干振荡持续，并在TR-ARPES谱中产生清晰的弗洛凯边带。这些激子场诱导的边带与泵浦激光场产生的不同，还识别出带隙与泵浦频率共振处残余相干导致的带共振诱导边带。最后分析了局部库仑相互作用极限。我们的结果证实了近期关于激子场诱导的类弗洛凯边带的实验观察，并确立DPOA是模拟相互作用电子系统中超快现象的有效且准确的方法。
英文摘要
We develop a theoretical framework based on the Dynamical Projective Operatorial Approach (DPOA) to study the time- and angle-resolved photoemission spectroscopy (TR-ARPES) of pumped excitonic systems. Including Coulomb electron-electron interactions at the Hartree-Fock (HF) level, our formalism captures the formation of excitonic bound states under the application of pump pulses. Considering a prototypical two-dimensional two-band semiconductor, we analyze the equilibrium phase diagram, which shows the expected transition from a semiconducting to an excitonic-insulator phase as the Coulomb interaction strength or its range increase. Out of equilibrium, we find that when the pump frequency is resonant with an excitonic mode, coherent oscillations of the excitonic order parameter persist after the pump pulse subsides and give rise to clear Floquet sidebands in the TR-ARPES spectrum. These exciton-field-induced sidebands are distinct from those originating from the pump laser field. We also identify band-resonance-induced sidebands arising from residual coherences at momenta where the band gap is resonant with the pump frequency. Finally, we analyze the local Coulomb interaction limit. Our results corroborate recent experimental observations of exciton-field-induced Floquet-like sidebands and establish DPOA as an efficient and accurate method for simulating ultrafast phenomena in interacting electron systems.
Comments14 pages, 8 figures, 34 panels
