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arXiv 2301.09668cond-mat.mtrl-sciphysics.chem-ph
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利用量子嵌入法研究固体中缺陷的光学性质

Optical properties of defects in solids via quantum embedding with good active space orbitals

Bryan T. G. Lau, Brian Busemeyer, Timothy C. Berkelbach

摘要:

固体中孤立缺陷的研究是经典或量子嵌入方法的自然目标,这些方法在高理论水平上处理缺陷,在低理论水平上处理固体的其余部分。在这里,在基于活性空间的量子嵌入的背景下,我们研究了三个活性空间轨道选择方案的性能的基础上规范(能量有序)轨道,本地定义的密度矩阵嵌入理论的精神,和近似的自然过渡轨道。利用单双激发的运动方程耦合团簇理论(CCSD),计算了六方氮化硼中碳二聚体缺陷、氧化镁中氧空位和金刚石中碳空位的垂直单重态激发能.特别是当与一个简单的复合校正结合使用时,我们发现,性能最好的方案可以预测的激发能约0.1-0.2 eV的收敛值使用只有几百个轨道,即使当整个超级电池有数千个轨道,这相当于许多数量级的计算节省时,使用相关的电子结构理论。当分配的实验光谱和占振动修正相比,我们发现,CCSD预测的激发能是准确的约0.1-0.3 eV,这是其在分子和散装固体的性能。

英文摘要:

The study of isolated defects in solids is a natural target for classical or quantum embedding methods that treat the defect at a high level of theory and the rest of the solid at a lower level of theory. Here, in the context of active-space-based quantum embeddings, we study the performance of three active-space orbital selection schemes based on canonical (energy-ordered) orbitals, local orbitals defined in the spirit of density matrix embedding theory, and approximate natural transition orbitals. Using equation-of-motion coupled-cluster theory with single and double excitations (CCSD), we apply these active space selection schemes to the calculation of the vertical singlet excitation energy of a substitutional carbon dimer defect in hexagonal boron nitride, an oxygen vacancy in magnesium oxide, and a carbon vacancy in diamond. Especially when used in combination with a simple composite correction, we find that the best performing schemes can predict the excitation energy to about 0.1-0.2 eV of its converged value using only a few hundred orbitals, even when the full supercell has thousands of orbitals, which amounts to many-orders-of-magnitude computational savings when using correlated electronic structure theories. When compared to assigned experimental spectra and accounting for vibrational corrections, we find that CCSD predicts excitation energies that are accurate to about 0.1-0.3 eV, which is comparable to its performance in molecules and bulk solids.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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