IMX Talks - Electron dynamics in materials from first principles

Recent progress in combining density functional theory with the Boltzmann equation are enabling spectacular advances in computing electron dynamics in materials from first principles. The interaction between electrons and lattice vibrations (phonons) plays a central role in these studies as it governs electron dynamics near room temperature. I will present our recently developed methods to compute electron-phonon interactions from first principles, and show how these advances enable calculations of charge transport and ultrafast dynamics in materials. The talk will focus on:
1) First-principles calculations of the carrier mobility, providing new insight into the mechanisms governing charge transport in semiconductors and oxides. I will discuss challenges for investigating complex materials, including those with polar bonds, structural phase transitions, strong electron-phonon interactions leading to polaron formation, and crystallographic defects.
2) Accurate simulations of materials out of equilibrium, focusing on a numerical approach to investigate the coupled ultrafast dynamics of electrons and phonons. I will demonstrate how this framework can compute time-domain absorption, diffraction and photoemission with quantitative accuracy in bulk and two-dimensional materials. Extensions to treat materials with strongly bound excitons will also be discussed.
3) Finally, I will highlight our efforts to develop an open source code, PERTURBO, that makes these new computational methods and workflows available to the community. The code’s unique capabilities, which will be described, equip us with broadly applicable quantitative tools to investigate electron interactions and dynamics in materials.
The talk will conclude with a discussion of the “quantum frontier” of this emerging field, focusing on studies of electron dynamics in quantum materials – both topological and correlated – and decoherence in qubit devices.
Bio: Marco Bernardi is assistant professor of Applied Physics and Materials Science at Caltech. He received his Ph.D. in Materials Science from MIT, where he worked with Prof. Jeff Grossman on novel materials and physical processes for solar energy conversion. He was a postdoc in the Physics Department at UC Berkeley, where, working with Profs. Steve Louie and Jeff Neaton, he developed new theoretical approaches for investigating excited electrons in materials. Marco's group at Caltech develops quantum mechanical calculations aimed at understanding the dynamics of electrons in materials, with application to electronics, optoelectronics, energy, quantum technologies and ultrafast science. Marco received the NSF CAREER Award in 2018, the AFOSR Young Investigator Award in 2017, the Psi-K Volker Heine Young Investigator Award for electronic structure calculations in 2015, and the Intel Ph.D. Fellowship in 2013. His work favors quantitative analysis and accurate computational approaches to understand the physics and potential applications of novel materials, charting new directions in materials theory.