TRR 360 Sonderseminar:

Computational design of quantum materials using density functional theory and beyond

Manish Verma

Computational design of quantum materials using density functional theory and beyond

Dr. Manish Verma

Institute for Theoretical Physics and Astrophysics
Computational Quantum Materials
Julius-Maximilians-Universität Würzburg

Computational design of quantum materials using density functional theory (DFT) and many-body techniques-both perturbative and non-perturbative, has become a powerful tool for exploring key physical phenomena such as strong correlations, metal-to-insulator transitions (MIT), magnetism, and thermoelectricity etc. In this direction, designing novel electronic properties in artificial transition metal oxide (TMO) heterostructures, distinct from their bulk counterparts, has emerged as a new paradigm enabled by modern layer-by-layer growth techniques and the unique nature of d-electrons. I will start my talk by discussing the mechanisms driving the MIT and magnetism in ultrashort-period superlattices (SL), namely (SrVO₃)₁/(SrTiO₃)₁(001) [1, 2] and (LaNiO₃)₁/(LaAlO₃)₁(001) [3], where confinement and epitaxial strain play fundamental roles. Subsequently, I will present the MIT in Ca-doped LaMnO₃, which arises from the interplay between strain and chemical doping [4]. TMO-based SL are also known to exhibit high thermoelectric response, in addition to their environmental friendliness and stability. In this context, I will discuss the doping-induced robust p-type thermoelectric response in ultrashort-period (SrMnO₃)₁/(SrTiO₃)₁(001) SL, obtained by employing Boltzmann transport theory within constant-relaxation time approach. Next, I will then present my results on strategies for reducing lattice thermal conductivity in artificial oxide superlattices, obtained using many-body perturbation theory calculations of phonon-phonon interactions. Transition-metal oxides are further known to display strong correlation effects due to their d-electrons. In this regard, LiV₂O₄ stands out as an enigmatic heavy fermion compound lacking localized f-orbital states. I will present DFT combined with dynamical mean-field theory (DFT+DMFT) results that elucidate the origin of heavy-fermion behavior, supported by angle-resolved photoemission spectroscopy (ARPES) measurements [5].

[1] M. Verma, B. Geisler, and R. Pentcheva, Phys. Rev. B 100, 165126 (2019).
[2] M. Verma and R. Pentcheva, Phys. Rev. Research 4, 033013 (2022).
[3] M. Verma and R. Pentcheva, Phys. Rev. Research 6 (1), 013189 (2024).
[4] S. S. Hong et al., Science 368, 71 (2020).
[5] D. Oh et al., Proceedings of the National Academy of Sciences 122 (45), e2518213122 (2025).