2025 IEEE NTC TC10 Modeling and Simulation September Webinar

Date: 29 September 2025

Time: 17:00 Madrid/Central European Summer Time (16:00 UK, 11:00 New York, 08:00 California)

Speaker: Prof. Juan José Palacios, Universidad Autónoma de Madrid

Title: XATU: A new toolbox for linear and non-linear optical response in 2D crystals

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Abstract

Understanding the optical response of two-dimensional (2D) crystals is essential for advancing next-generation technologies in photonics, optoelectronics, and quantum information. These materials exhibit unique light–matter interactions due to their reduced dimensionality, strong excitonic effects, and tunable symmetry-driven selection rules, which give rise to phenomena such as the bulk photovoltaic effect, second-harmonic generation, and complex exciton dynamics. Accurately modeling their linear and non-linear optical properties is therefore crucial not only for interpreting experimental observations but also for guiding the design of efficient light-harvesting devices, photodetectors, and ultrafast switches based on these 2D systems.

This webinar presents recent advances in the theoretical and computational modeling of the optical response of 2D crystals using the Xatu ecosystem — a suite of tools recently designed to address linear and non-linear optical phenomena, including excitonic effects, within various degrees of computational complexity. The presentation highlights how different modules such as Xatu.Wannier and Xatu.GTF, enable both effective (Wannier-based) and many-body (GW-BSE) treatments of excitons, respectively, allowing for from acceptable to accurate calculations of the optical response (Xatu.OptiX) in both the linear (absorption) and non-linear –e.g., bulk photovoltaic effect (BPVE), second harmonic generation, etc.– regimes. A particular focus will be placed on the BPVE for several 2D materials — such as MoS₂, GeS, and hBN as case studies. The presentation concludes with perspectives on the extension of these methods to multilayers and Moiré systems, suggesting rich avenues for future exploration in ultrafast optoelectronics and quantum materials.

Bio

Juan José Palacios (Full Professor) has an extensive career as a Condensed Matter Physics theoretician, expanding 3 decades and having worked on a wide variety of problems at different international institutions (Canada Research Council, Indiana University, University of Kentucky, Universidad de Alicante, Instituto de Ciencia de Materiales de Madrid, and University of Texas at Austin as a Fulbright scholar). Since 2009 he works at the department of Condensed Matter Physics and Condensed Matter Physics Institute (Universidad Autónoma de Madrid) where he has taught courses at all levels and has supervised 15 PhD students, currently supervising 5 PhD students more.

He appears in the top 2% in the Stanford list of most relevant scientists. In the context of computational studies and simulations one could refer to his pioneering work in molecular electronics through one of first the implementations of quantum transport from first principles, Atomistic NanoTransport (ANT), which is freely distributed (https://github.com/juanjosepalacios/ANT.Gaussian). He co-founded SIMUNE Atomistics (https://www.simuneatomistics.com), the first company in Spain that offers computational services for material science related industrial needs.

Over the past ten years, his research in molecular electronics has actively continued with novel studies of chirality induced spin selectivity but has extended to other fields such as graphene and two-dimensional crystals and topological or quantum materials. In this context, to name a few relevant examples, he has published several highly cited papers on the theory of graphene magnetism (over 2500) citations, including the first evidence of hydrogen-induced magnetism in graphene and published in Science (700 citations) and participated in a pioneering publication reporting the possibility of exfoliating and measuring the properties of a monolayer of black-phosphorous (phosphorene), which has received almost 2000 citations to date. His most recent works include studies of the linear and nonlinear optical excitonic response of 2D materials, which are based on a newly developed computational platform (XATU, https://github.com/xatu-code).