Detection and Correction of Delocalization Errors for Electron and Hole Polarons Using Density-Corrected DFT
Detection and Correction of Delocalization Errors for Electron and Hole Polarons Using Density-Corrected DFT
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使用密度校正 DFT 检测和校正电子和空穴极化子的离域误差
DOI：
10.1021/acs.jpclett.2c01187
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Herbert, John M.
中科院分区：
文献类型：
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作者：
Rana, Bhaskar;Coons, Marc P.;Herbert, John M.
极化子缺陷的模拟是计算材料科学的一个重要方面，但密度泛函理论（DFT）中对非成对自旋的描述经常会出现离域误差。为了诊断和校正自旋缺陷的过离域，我们报告了密度校正（DC-）DFT及其解析能量梯度的实现。在DC-DFT中，使用Hartree-Fock密度评估交换相关泛函，从而在避免自相互作用误差的同时并入电子相关。二氧化钛模型中的电子极化子和铝掺杂二氧化硅中的空穴极化子的结果表明，半局域泛函的几何优化驱动显着的结构畸变，包括几个键的伸长，使得随后的单点计算与混合泛函未能提供局部缺陷，即使在与混合泛函的几何优化局部化极化子的情况下。这对计算材料科学中的传统工作流程具有重要意义，其中半局部泛函通常用于结构松弛。DC-DFT计算提供了一种检测离域误差可能影响结果的情况的机制。
Modeling polaron defects is an important aspect of computational materials science, but the description of unpaired spins in density functional theory (DFT) often suffers from delocalization error. To diagnose and correct the overdelocalization of spin defects, we report an implementation of density-corrected (DC-)DFT and its analytic energy gradient. In DC-DFT, an exchange-correlation functional is evaluated using a Hartree–Fock density, thus incorporating electron correlation while avoiding self-interaction error. Results for an electron polaron in models of titania and a hole polaron in Al-doped silica demonstrate that geometry optimization with semilocal functionals drives significant structural distortion, including the elongation of several bonds, such that subsequent single-point calculations with hybrid functionals fail to afford a localized defect even in cases where geometry optimization with the hybrid functional does localize the polaron. This has significant implications for traditional workflows in computational materials science, where semilocal functionals are often used for structure relaxation. DC-DFT calculations provide a mechanism to detect situations where delocalization error is likely to affect the results.