Electronic structure and optical properties of quantum crystals from first principles calculations in the Born?Oppenheimer approximation [electronic resource]

• Ngôn ngữ: eng
• Ký hiệu phân loại: 541 Physical chemistry
• Thông tin xuất bản: Washington, D.C. : Oak Ridge, Tenn. : United States. National Nuclear Security Administration ; Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2020
• Mô tả vật lý: Size: Article No. 234117 : , digital, PDF file.
• Bộ sưu tập: Metadata
• ID: 261735
• Chủ đề: 1. 37 inorganic, organic, physical, and analytical chemistry; 2. 60 applied life sciences; 3. 71 classical and quantum mechanics, general physics; 4. Band gap; 5. Chemistry; 6. Electronic structure; 7. Et al; 8. Monte carlo methods; 9. Optical absorption; 10. Physics; 11. Statistical thermodynamics

Tóm tắt

In this work, we develop a formalism to accurately account for the renormalization of the 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 the 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 200 K and 250 GPa and discuss the optical absorption profile of hydrogen crystals at 200 K and carbon diamond at 297 K.