EPW is an open-source software for ab initio calculations of electron–phonon interactions and related materials properties.The code combines density functional perturbation theory and maximally localized Wannier func...EPW is an open-source software for ab initio calculations of electron–phonon interactions and related materials properties.The code combines density functional perturbation theory and maximally localized Wannier functions to efficiently compute electron–phonon coupling matrix elements,and to perform predictive calculations of temperature-dependent properties and phonon-assisted quantum processes in bulk solids and low-dimensional materials.Here,we report on significant developments in the code since 2016,namely:a transport module for the calculation of charge carrier mobility under electric and magnetic fields using the Boltzmann transport equation;a superconductivity module for calculations of phonon-mediated superconductors using the anisotropic multi-band Eliashberg theory;an optics module for calculations of phonon-assisted indirect transitions;a module for the calculation of small and large polarons without supercells;and a module for calculating band structure renormalization and temperature-dependent optical spectra using the special displacement method.For each capability,we outline the methodology and implementation and provide example calculations.展开更多
Using first principles techniques,we show that infrared optical response allows us to discriminate between the topological and the trivial phases of 2D quantum spin Hall insulators(QSHI).We showcase germanene and jacu...Using first principles techniques,we show that infrared optical response allows us to discriminate between the topological and the trivial phases of 2D quantum spin Hall insulators(QSHI).We showcase germanene and jacutingaite,of recent experimental realization,as prototypical systems where the infrared spectrum is discontinuous across the transition,due to sudden and large discretized jumps of the Born effective charges(up to~2).Our results,rationalized thanks to the lowenergy Kane–Mele model,are robust with respect to dynamical effects,relevant when the electronic energy gap is comparable with the phonon frequency.In the small gap QSHI germanene,due to dynamical effects,the in-plane phonon resonance in the optical conductivity shows a Fano profile with remarkable differences in the intensity and the shape between different phases.Instead,the large-gap QSHI jacutingaite presents several IR-active phonon modes whose spectral intensities drastically change between different phases.展开更多
基金This research is supported by:the Computational Materials Sciences Program funded by the U.S.Department of Energy,Office of Science,Basic Energy Sciences,under Award No.DE-SC0020129(project coordination,scale-up,polaron module,transport module,optics module,special displacement module)the National Science Foundation,Office of Advanced Cyberinfrastructure and Division of Materials Research under Grants Nos.2103991 and 2035518(superconductivity module,interoperability)+12 种基金the NSF Characteristic Science Applications for the Leadership Class Computing Facility program under Grant No.2139536(prepara-tion for LCCF)the Fond National de la Recherche Scientifique of Belgium(F.R.S.-FNRS)and the European Union’s Horizon 2020 research and innovation program under grant agreements No.881603-Graphene Core3(transport module)the NSF DMREF award 2119555(quasi-degenerate perturbation theory module)This research used resources of the National Energy Research Scientific Computing Center and the Argonne Leadership Computing Facility,which are DOE Office of Science User Facilities supported by the Office of Science of the U.S.Department of Energy,under Contracts No.DE-AC02-05CH11231 and DE-AC02-06CH11357,respectivelyThe authors acknowledge the Texas Advanced Computing Center(TACC)at The University of Texas at Austin for providing access to Frontera,Lonestar6,and Texascale Days,which have contributed to the research results reported within this paper(http://www.tacc.utexas.edu)the Extreme Science and Engineering Discovery Environment(XSEDE)218 which is supported by National Science Foundation grant number ACI-1548562in particular Expanse at the San Diego Supercomputer Center through allocation TG-DMR180071.S.Packnowl-edges computational resources provided by the PRACE award granting access to Discoverer in SofiaTech,Bulgaria(OptoSpin project id.2020225411)by the Consortium desÉquipements de Calcul Intensif(CÉCI),funded by the FRS-FNRS under Grant No.2.5020.11the Walloon Region,as well as computational resources awarded on the Belgian share of the EuroHPC LUMI supercomputer.K.B.acknowledges the support of the U.S.Department of Energy,Office of Science,Office of Advanced Scientific Computing Research,Department of Energy Computational Science Graduate Fellowship under Award Number DE-SC0020347The authors wish to thank Zhenbang Dai,Nikolaus Kandolf,Viet-Anh Ha,and Amanda Wang for their contributions to the EPW project that are not discussed in this manuscriptJohn Cazes and Hang Liu at TACC for their support with the Characteristic Science Applications project,Paolo Giannozzi for his support with Quantum ESPRESSOStefano Baroni for fruitful discussions.
文摘EPW is an open-source software for ab initio calculations of electron–phonon interactions and related materials properties.The code combines density functional perturbation theory and maximally localized Wannier functions to efficiently compute electron–phonon coupling matrix elements,and to perform predictive calculations of temperature-dependent properties and phonon-assisted quantum processes in bulk solids and low-dimensional materials.Here,we report on significant developments in the code since 2016,namely:a transport module for the calculation of charge carrier mobility under electric and magnetic fields using the Boltzmann transport equation;a superconductivity module for calculations of phonon-mediated superconductors using the anisotropic multi-band Eliashberg theory;an optics module for calculations of phonon-assisted indirect transitions;a module for the calculation of small and large polarons without supercells;and a module for calculating band structure renormalization and temperature-dependent optical spectra using the special displacement method.For each capability,we outline the methodology and implementation and provide example calculations.
文摘Using first principles techniques,we show that infrared optical response allows us to discriminate between the topological and the trivial phases of 2D quantum spin Hall insulators(QSHI).We showcase germanene and jacutingaite,of recent experimental realization,as prototypical systems where the infrared spectrum is discontinuous across the transition,due to sudden and large discretized jumps of the Born effective charges(up to~2).Our results,rationalized thanks to the lowenergy Kane–Mele model,are robust with respect to dynamical effects,relevant when the electronic energy gap is comparable with the phonon frequency.In the small gap QSHI germanene,due to dynamical effects,the in-plane phonon resonance in the optical conductivity shows a Fano profile with remarkable differences in the intensity and the shape between different phases.Instead,the large-gap QSHI jacutingaite presents several IR-active phonon modes whose spectral intensities drastically change between different phases.
