Upcoming Event: Oden Institute & Dept. of Physics

Towards the Predictive First-Principles Modeling of Finite-Temperature Quantum Materials

Antonios Alvertis, Research Scientist, NASA Ames Research Center

Abstract

Understanding the microscopic properties of quantum materials is critical towards designing novel energy technologies. Decades of research has resulted in increasingly accurate ways of modeling electron-electron interactions, as well as the interactions between electrons and positively charged holes, which underlie several of the application-relevant properties of quantum materials. However, a factor which is often disregarded in describing such electronic properties is atomic motion, which is present not only at finite temperatures, but even at absolute zero. In this talk, I will present different theoretical methods that I have developed in order to account for the effects of atomic motion on electronic interactions, and I will show examples of how atomic motion can radically alter the physics of diverse quantum materials. Specifically, I will show that temperature can reduce the binding energy of optically excited states by 70% in diverse semiconductors and insulators, and that interlayer atomic motion can greatly renormalize the excited state properties of 2D heterostructures. I will demonstrate that zero-point motion substantially modifies the electronic wave function of molecular crystals, revealing a pathway towards rapid energy transfer in photovoltaics, and how this allowed me to minimize heat losses in organic crystals, achieving some of the world’s most efficient LEDs.

Biography

Antonios Alvertis is a research scientist at the NASA Ames Research Center, where he explores ways of combining high-performance computing and quantum computing technologies, in order to understand the properties of complex quantum materials. He moved to the USA in 2021, on a joint postdoctoral research fellowship from the Cambridge University and UC Berkeley Physics departments, and then stayed on as a postdoc at Lawrence Berkeley National Lab until August of 2023. During this time, he developed theoretical methods and software packages for accurately describing the excited state properties of diverse solids, and accounting for the effects of temperature on their physics. For this work he received the Theoretical Physics award of the Academy of Athens in December of 2024. Prior to his time in Berkeley, he worked towards his Ph.D. in Physics from the University of Cambridge, and in 2021 his thesis was awarded the Cavendish Ph.D. prize and the Springer Thesis award, recognizing the contributions of his theoretical work in elucidating the complex photophysics of organic chromophores.