论文标题
量子晶体的电子结构和光学特性，来自第一原理计算
Electronic structure and optical properties of quantum crystals from first principles calculations in the Born-Oppenheimer approximation
论文作者
论文摘要
我们开发一种形式主义，以准确地说明由于出生的烟囱近似值内的量子和热核运动而导致电子结构的重新归一化。我们专注于从规范或大规范集合中从量子蒙特卡洛计算中获得的电子添加和去除能量获得的基本能隙。形式主义也适用于有效的单电子理论，例如基于密度功能理论的理论。我们表明，可以通过将总电子波功能相对于核能分布来恢复电子（BLOCH）晶体动量，我们描述了一个明确的程序，以建立出生的 - 浓度近代近似值中量子晶体的电子激发的带状结构。基于Kubo-Greenwood方程，我们讨论了核运动对光导率的影响。我们的方法适用于量化核运动的低温状态，并且通常与半古典近似不同。我们应用我们的方法来研究200K和250 GPA的C2/C-24晶体氢的电子结构，并讨论200K氢晶体的光吸收曲线和297K的碳钻石。
We develop a formalism to accurately account for the renormalization of electronic structure due to quantum and thermal nuclear motions within the Born-Oppenheimer approximation. We focus on the fundamental energy gap obtained from electronic addition and removal energies from Quantum Monte Carlo calculations in either the canonical or grand canonical ensembles. The formalism applies as well to effective single electron theories such as those based on Density Functional Theory. We show that electronic (Bloch) crystal momentum can be restored by marginalizing the total electron-ion wave function with respect to the nuclear equilibrium distribution, and we describe an explicit procedure to establish the band structure of electronic excitations for quantum crystals within the Born-Oppenheimer approximation. Based on the Kubo-Greenwood equation, we discuss the effects of nuclear motion on optical conductivity. Our methodology applies to the low temperature regime where nuclear motion is quantized and in general differs from the semi-classical approximation. We apply our method to study the electronic structure of C2/c-24 crystalline hydrogen at 200K and 250 GPa and discuss the optical absorption profile of hydrogen crystal at 200K and carbon diamond at 297K.
