Title: Field-tunable light-matter interaction in van der Waals matter
Abstract: Van der Waals matter - systems composed of natural or artificially stacked two-dimensional layered materials - is highly sensitive to both interlayer interactions and external perturbations. The strategic stacking of distinct layered materials provides a powerful route toward emergent electronic phases and strongly interacting many-body optical excitations. In particular, transition metal dichalcogenide (TMDC) semiconductors offer a fertile playground to engineer and control light-matter interaction through tunable electronic and excitonic degrees of freedom. In this talk, I will discuss how external electric and magnetic fields enable tunable control of electronic structure and excitonic properties in TMDC-based van der Waals systems. I will discuss: (i) a generalized many-body theory of exciton magnetic moments applied to monolayer TMDCs[1]; (ii) robust electrical control of multivalley intersubband transitions in few-layer TMDCs[2]; and (iii) the emergence of giant magnetic moments for neutral excitons in alloyed TMDCs[3]. [1] Phys. Rev. B (Letters) 112, L241404 (2025). [2] ACS Nano 20, 4018 (2026). [3] Phys. Rev. Lett (Editors' Suggestion) 136, 076901 (2026).
About the Speaker: Dr. Paulo Eduardo de Faria Junior received his BSc (2009), MSc (2012), and PhD (2016) degrees in Computational Physics from the University of São Paulo, Brazil. During his PhD, he spent one year at SUNY Buffalo as an exchange student. In 2017, he moved to the University of Regensburg (UR), Germany, as a postdoctoral fellow funded by the Alexander von Humboldt Foundation (Germany) and CAPES (Brazil). He remained at UR as a postdoctoral researcher (2019-2021) and research associate (2021-2024), acquiring his Habilitation in 2024. Since December 2024, he has joined UCF as an Assistant Professor in the Department of Physics with a joint appointment in the Department of Electrical and Computer Engineering. His research group covers a broad range of topics in theoretical and computational condensed matter physics with a strong overlap with materials science. The group employs and develops novel computational approaches based on first-principles (ab initio) methodologies, effective Hamiltonians, and group theory analysis to study the fundamental aspects and potential applications of various quantum materials in the fields of optoelectronics, optospintronics, and quantum information technology.
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