Research themes#
Our group works at the interface between condensed matter theory, quantum materials research, and high-performance computing. We develop computational methods to predict the properties of materials at the atomic scale, starting from the first principles of quantum mechanics. Our activities span fundamental theory, algorithm and software development, and the application of these tools to technologically-relevant materials. We frequently collaborate with experimental groups to interpret complex measurements and to discover new materials that have not yet been realized in the laboratory.
Electron-phonon physics#
The interaction between electrons and phonons [1], the quanta of lattice vibrations, governs many important phenomena in materials, from electrical and thermal transport to superconductivity and ultrafast carrier dynamics. A central focus of our group is to develop theoretical and computational frameworks that describe these interactions with predictive accuracy using quantum many-body methods.
We work on:
Many-body Green’s function approaches to electron-phonon physics [2]
Wannier-Fourier interpolation schemes for electron-phonon coupling matrix elements [3]
Quantum zero-point and temperature-induced renormalization of electron band structures [4]
Phonon-assisted optical processes [5]
Electrical and thermal transport [6]
Interpretation of photoemission spectroscopy and ultrafast spectroscopy [7]
Emergent phenomena#
Emergent phenomena arise when the coupled dynamics of electrons, phonons, spins, or photons produce collective behaviors that cannot be inferred from the properties of individual particles. One research direction of our group is to develop ab initio many-body frameworks to explain how such complex quasiparticles form, evolve, and manifest in experiments. The polaron, i.e., an electron dressed by a distortion of the crystal lattice, represents an example of emergent quasiparticle in solids. We work toward a quantitative and predictive understanding of these quasiparticles across regimes ranging from small, strongly localized Holstein-type polarons to large, delocalized Fröhlich quasiparticles, all within a unified first-principles formalism. These ideas are currently being generalized to other emergent excitations, including topological quasiparticles.
Recent work in this area includes:
Light-matter interactions#
We investigate how light couples to matter, and how optical absorption and emission spectra carry the signatures of this interaction. We ar eprimarily interested in regimes where electrons, holes, excitons, photons, and phonons interact to produce rich composite excitation with distinctive spectral fingerprints. This work involves the development of new electronic-structure methods, algorithms, and software for studying excitonic effects, phonon-mediated optical transitions, and exciton-phonon couplings.
Recent work includes:
Semiconductors#
A large part of our work is devoted to the design and discovery of semiconductors for next-generation electronics. We work closely with experimental collaborators to identify, characterize, and design materials with improved carrier transport properties in extreme regimes, for example in ultrascaled transistors or in high-power applications.
Current research directions include:
High-throughput searches of 2D atomically-thin semiconductors with high carrier mobilities [14]
Computational design of wide-bandgap semiconductors for high-power, high-frequency, and radiation-hard applications [15]
Assessment of the viabilit of p-type oxides for back-end-of-the-line applications in next-generation chips. [16]
Materials discovery#
We often use first-principles approaches to designing entirely new materials from scratch. Our work combines high-throughput ab initio screening and advanced electronic-structure methods to identify materials with targeted optical and electronic properties. Much of this research focuses on sustainable and functional semiconductors for optoelectronics, with an emphasis on materials that can be discovered and optimized through a closed theory–experiment feedback loop.
Successful predictions include:
We identified lead-free alternatives to lead-based perovskites, and several compounds that we predicted have been synthesized, for example Cs₂AgInCl₆, the first single-material white-light emitter [17]
We identified a novel nitride perovskite, CeTaN₃, and predicted that it could be a potential ferroelectric semiconductor [18]; our prediction was subsequently confirmed by experiments
Software, HPC, and ML/AI#
Much of our time is devoted to developing open-source software for advanced quantum materials simulations. We design, implement, and maintain large-scale codes for leadership-class supercomputers, with a focus on predictive electronic-structure methods, electron-phonon interactions, many-body perturbation theory, and automated high-throughput workflows. All the code generated by our group is open-source and is continuously shared with the community without any restrictions.
We currently maintain several software projects (see the software page for more details):
Feliciano Giustino. Electron-phonon interactions from first principles. Rev. Mod. Phys., 89(1):015003, 2017. doi:10.1103/RevModPhys.89.015003.
Jon Lafuente-Bartolome, Chao Lian, Weng Hong Sio, Idoia G Gurtubay, Asier Eiguren, and Feliciano Giustino. Unified approach to polarons and phonon-induced band structure renormalization. Phys. Rev. Lett., 129(7):076402, 2022. doi:10.1103/PhysRevLett.129.076402.
Feliciano Giustino, Jonathan R Yates, Ivo Souza, Marvin L Cohen, and Steven G Louie. Electron-phonon interaction via electronic and lattice Wannier functions: Superconductivity in boron-doped diamond reexamined. Phys. Rev. Lett., 98(4):047005, 2007. doi:10.1103/PhysRevLett.98.047005.
Feliciano Giustino, Steven G Louie, and Marvin L Cohen. Electron-phonon renormalization of the direct band gap of diamond. Phys. Rev. Lett., 105(26):265501, 2010. doi:10.1103/PhysRevLett.105.265501.
Marios Zacharias, Christopher E Patrick, and Feliciano Giustino. Stochastic approach to phonon-assisted optical absorption. Phys. Rev. Lett., 115(17):177401, 2015. doi:10.1103/PhysRevLett.115.177401.
Samuel Poncé, Wenbin Li, Sven Reichardt, and Feliciano Giustino. First-principles calculations of charge carrier mobility and conductivity in bulk semiconductors and two-dimensional materials. Rep. Prog. Phys., 83(3):036501, 2020. doi:10.1088/1361-6633/ab6a43.
Carla Verdi, Fabio Caruso, and Feliciano Giustino. Origin of the crossover from polarons to Fermi liquids in transition metal oxides. Nat. Commun., 8:15769, 2017. doi:10.1038/ncomms15769.
Weng Hong Sio, Carla Verdi, Samuel Poncé, and Feliciano Giustino. Polarons from first principles, without supercells. Phys. Rev. Lett., 122(24):246403, 2019. doi:10.1103/PhysRevLett.122.246403.
Jon Lafuente-Bartolome, Chao Lian, and Feliciano Giustino. Topological polarons in halide perovskites. Proc. Natl. Acad. Sci. U.S.A., 121(21):e2318151121, 2024. doi:10.1073/pnas.231815112.
Zhenbang Dai and Feliciano Giustino. Identification of large polarons and exciton polarons in rutile and anatase polymorphs of titanium dioxide. Proc. Natl. Acad. Sci. U.S.A., 121(48):e2414203121, 2024. doi:10.1073/pnas.2414203121.
Zhenbang Dai, Chao Lian, Jon Lafuente-Bartolome, and Feliciano Giustino. Theory of excitonic polarons: From models to first-principles calculations. Phys. Rev. B, 109(4):045202, 2024. doi:10.1103/physrevb.109.045202.
Sabyasachi Tiwari, Emmanouil Kioupakis, José Menendez, and Feliciano Giustino. Unified theory of optical absorption and luminescence including both direct and phonon-assisted processes. Phys. Rev. B, 109(19):195127, 2024. doi:10.1103/PhysRevB.109.195127.
Zhenbang Dai, Chao Lian, Jon Lafuente-Bartolome, and Feliciano Giustino. Excitonic polarons and self-trapped excitons from first-principles exciton-phonon couplings. Phys. Rev. Lett., 132(3):036902, 2024. doi:10.1103/physrevlett.132.036902.
Viet-Anh Ha and Feliciano Giustino. High-throughput screening of 2D materials identifies p-type monolayer WS₂ as potential ultra-high mobility semiconductor. npj Comput. Mater., 10(1):229, 2024. doi:10.1038/s41524-024-01417-0.
Jie-Cheng Chen, Joshua Leveillee, Chris G Van de Walle, and Feliciano Giustino. Design of high-mobility p-type GaN via the piezomobility tensor. Phys. Rev. Mater., 9(8):084602, 2025. doi:10.1103/z22d-vlvc.
Sieun Chae, Seungmin Lee, Anna Park, MK Senevirathna, Yufan Feng, Venkanna Kanneboina, Viet-Anh Ha, Yaoqiao Hu, Chaojie Du, Matthew Barone, and others. Controlling the p-type conductivity of α-SnO thin films by potassium doping. APL Mater., 2025. doi:10.1063/5.0288742.
George Volonakis, Amir A Haghighirad, Rebecca L Milot, Weng H Sio, Marina R Filip, Bernard Wenger, Michael B Johnston, Laura M Herz, Henry J Snaith, and Feliciano Giustino. Cs₂InAgCl₆: A new lead-free halide double perovskite with direct band gap. J. Phys. Chem. Lett., 8(4):772, 2017. doi:10.1021/acs.jpclett.6b02682.
Viet-Anh Ha, Hyungjun Lee, and Feliciano Giustino. CeTaN₃ and CeNbN₃: Prospective nitride perovskites with optimal photovoltaic band gaps. Chem. Mater., 34(5):2107, 2022. doi:10.1021/acs.chemmater.1c03503.
Hyungjun Lee, Samuel Poncé, Kyle Bushick, Samad Hajinazar, Jon Lafuente-Bartolome, Joshua Leveillee, Chao Lian, Jae-Mo Lihm, Francesco Macheda, Hitoshi Mori, and others. Electron-phonon physics from first principles using the EPW code. npj Comput. Mater., 9(1):156, 2023. doi:10.1038/s41524-023-01107-3.
Martin Schlipf, Henry Lambert, Nourdine Zibouche, and Feliciano Giustino. SternheimerGW: A program for calculating GW quasiparticle band structures and spectral functions without unoccupied states. Comp. Phys. Commun., 247:106856, 2020. doi:10.1016/j.cpc.2019.07.019.