Predominance of non-adiabatic effects in zero-point renormalization of the electronic band gap
Anna Miglio, Véronique Brousseau-Couture, Emile Godbout, Gabriel Antonius, Yang-Hao Chan, Steven G. Louie, Michel Côté, Matteo Giantomassi, Xavier Gonze
备注：
Note that the supplementary material, included in the main file, is structured differently than in the published version, with a different numbering scheme
Electronic and optical properties of materials are affected by atomic motion through the electron-phonon interaction: not only band gaps change with temperature, but even at absolute zero temperature, zero-point motion causes band-gap renormalization. We present a large-scale first-principles evaluation of the zero-point renormalization of band edges beyond the adiabatic approximation. For materials with light elements, the band gap renormalization is often larger than 0.3 eV, and up to 0.7 eV. This effect cannot be ignored if accurate band gaps are sought. For infrared-active materials, global agreement with available experimental data is obtained only when non-adiabatic effects are taken into account. They even dominate zero-point renormalization for many materials, as shown by a generalized Fröhlich model that includes multiple phonon branches, anisotropic and degenerate electronic extrema, whose range of validity is established by comparison with first-principles results.
We investigate non-adiabatic effects on the magnon frequency in an interacting system of localized spins and itinerant electrons. Including the lowest order corrections to the adiabatic dynamics in an analytically solvable model, applicable to simple ferromagnets like Fe, Co and Ni, we find that the magnon frequency is renormalized by a geometrical torque arising from the electronic spin Berry curvature. Comparison to exact numerical simulations reveals that our analytical solution captures essential low-energy features, and provides a mechanism for the magnon frequency hardening observed in r…
Importance of Non-Adiabatic Effects on Kohn Anomalies in 1D metals
Université catholique de Louvain（天主教鲁汶大学）；Institute of Condensed Matter and Nanosciences, Université catholique de Louvain（天主教鲁汶大学凝聚态物质与纳米科学研究所）；WEL Research Institute（WEL研究所）；School of Materials Science and Engineering, Northwestern Polytechnical University（西北工业大学材料科学与工程学院）
Effect of spin-orbit coupling on the zero-point renormalization of the electronic band gap in cubic materials: First-principles calculations and generalized Fröhlich model
The adiabatic Born-Oppenheimer approximation is considered to be a robust approach that very rarely breaks down. Consequently, it is predominantly utilized to address various electron-phonon properties in condensed matter physics. By combining many-body perturbation and density functional theories we demonstrate the importance of dynamical (nonadiabatic) effects in estimating superconducting properties in various bulk and two-dimensional materials. Apart from the expected long-wavelength nonadiabatic effects, we found sizable nonadiabatic Kohn anomalies away from the Brillouin zone center for …
In this comparative study we benchmark a recently developed non-adiabatic exchange-correlation potential within time-dependent density functional theory (TDDFT) (Phys.\ Rev.\ Lett.\ {\bf 120}, 157701 (2018)) by (a) validating the transient dynamics using a numerically exact density matrix renormalization group approach as well as by (b) comparing the $RC$-time, a typical linear response quantity, to upto second order perturbation theory results. As a testbed we use the dynamics of the single impurity Anderson model. These benchmarks show that the non-adiabatic functional yields quantitatively …
We present a method to efficiently combine the computation of electron-electron and electron-phonon self-energies, which enables the evaluation of electron-phonon coupling at the $G_0W_0$ level of theory for systems with hundreds of atoms. In addition, our approach, which is a generalization of a method recently proposed for molecules [J. Chem. Theory Comput. 2018, 14, 6269-6275], enables the inclusion of non-adiabatic and temperature effects at no additional computational cost. We present results for diamond and defects in diamond and discuss the importance of numerically accurate $G_0W_0$ ba…
Application of the exact-factorization density-functional perturbation approach to pentacene crystal and monolayer MoS2
Weizmann Institute of Science（魏茨曼科学研究所）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）；Tsientang Institute of Advanced Study（紫江高等研究院）；The Hebrew University of Jerusalem（耶路撒冷希伯来大学）；Ruđer Bošković Institute（鲁杰·博什科维奇研究所）
We benchmark a set of quantum-chemistry methods, including multitrajectory Ehrenfest, fewest-switches surface-hopping, and multiconfigurational-Ehrenfest dynamics, against exact quantum-many-body techniques by studying real-time dynamics in the Holstein model. This is a paradigmatic model in condensed matter theory incorporating a local coupling of electrons to Einstein phonons. For the two-site and three-site Holstein model, we discuss the exact and quantum-chemistry methods in terms of the Born-Huang formalism, covering different initial states, which either start on a single Born-Oppenheime…
