来自贝塞耳-萨尔皮特方程的解析力用于大规模激发态弛豫
Analytical Forces from the Bethe-Salpeter Equation for Large-Scale Excited-State Relaxation
AI总结：
该研究提出用于BSE描述的电子激发态的解析核力的高效平面波实现方法，结合密度矩阵微扰理论与拉格朗日方法及GPU加速，使计算可行，通过两个点缺陷验证，为非均匀凝聚系统相关研究建立可扩展框架。
AI中文摘要：
我们提出了一种用于由贝塞耳-萨尔皮特方程（BSE）描述的电子激发态的解析核力的高效平面波实现方法。该公式将密度矩阵微扰理论与拉格朗日方法相结合，避免了传统基于密度泛函微扰理论方法所需的显式空态求和以及每个原子位移的响应计算。结合GPU加速，这些进展使含数百个原子的固态系统的BSE力计算变得可行。我们在具有不同介电环境的两个点缺陷上展示了该方法：金刚石中的氮空位中心，BSE和含时密度泛函理论（TDDFT）产生一致的激发态弛豫；二维六方氮化硼中的碳二聚体缺陷，BSE中包含的屏蔽电子-空穴相互作用稳定了局部缺陷激发并修正了半局部TDDFT预测的弛豫模式。这些结果为非均匀凝聚系统中激发态弛豫和振动耦合的BSE级研究建立了一个可扩展的框架。
英文摘要：
We present an efficient plane-wave implementation of analytical nuclear forces for electronic excited states described by the Bethe-Salpeter equation (BSE). The formulation combines density-matrix perturbation theory with a Lagrangian approach, and avoids both explicit empty-state summations and the response calculations for each atomic displacement, required by conventional approaches based on density functional perturbation theory. Together with GPU acceleration, these advances make BSE forces calculations tractable for solid-state systems containing hundreds of atoms. We demonstrate the method on two point defects with distinct dielectric environments: the nitrogen-vacancy center in diamond, where BSE and time-dependent density functional theory (TDDFT) yield consistent excited-state relaxations, and the carbon-dimer defect in two-dimensional hexagonal boron nitride, where the screened electron-hole interaction included in the BSE stabilizes the localized defect excitation and corrects the relaxation pattern predicted by semilocal TDDFT. These results establish a scalable framework for BSE-level studies of excited-state relaxation and vibronic coupling in heterogeneous condensed systems.
