Affiliation:
1. Department of Semiconductor Materials Engineering Wrocław University of Science and Technology Wrocław 50‐370 Poland
2. Department of Physics and Earth Sciences Jacobs University Bremen Campus Ring 1 28759 Bremen Germany
3. Helmholtz‐Zentrum Dresden‐Rossendorf Abteilung Ressourcenökologie Forschungsstelle Leipzig Permoserstr. 15 04318 Leipzig Germany
4. Institute for Theoretical Physics University of Regensburg Universitätsstraße 31 93040 Regensburg Germany
5. Institut für Physik Carl von Ossietzky Universität Oldenburg 26129 Oldenburg Germany
Abstract
AbstractMA2Z4 monolayers form a new class of hexagonal non‐centrosymmetric materials hosting extraordinary spin‐valley physics. While only two compounds (MoSi2N4 and WSi2N4) are recently synthesized, theory predicts interesting (opto)electronic properties of a whole new family of such two‐dimensional (2D) materials. Here, the chemical trends of band gaps and spin‐orbit splittings of bands in selected MSi2Z4 (M = Mo, W; Z = N, P, As, Sb) compounds are studied from first‐principles. Effective Bethe–Salpeter‐equation‐based calculations reveal high exciton binding energies. Evolution of excitonic energies under external magnetic field is predicted by providing their effective g‐factors and diamagnetic coefficients, which can be directly compared to experimental values. In particular, large positive g‐factors are predicted for excitons involving higher conduction bands. In view of these predictions, MSi2Z4 monolayers yield a new platform to study excitons and are attractive for optoelectronic devices, also in the form of heterostructures. In addition, a spin‐orbit induced bands inversion is observed in the heaviest studied compound, WSi2Sb4, a hallmark of its topological nature.
Funder
Deutsche Forschungsgemeinschaft
Narodowe Centrum Nauki
Volkswagen Foundation
Subject
Biomaterials,Biotechnology,General Materials Science,General Chemistry
Cited by
10 articles.
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