Theorie halbleitender Moiré-Materialien
Zusammenfassung der Projektergebnisse
Our goal was elucidation of the interplay between structural relaxation and electronic properties in moire materials, in particular emergent electronic properties. The project has been very successful as documented by 8 published papers describing the key scientific achievements. In two papers on bilayer graphene we combined large scale continuum calculations (based on an underlying tight-binding method) with state-of-the-art structural relaxation obtained via the LAMMPS software package (combining the general Amber force field (GAFF) with the registry-dependent Kolmogorov-Crespi potential). These reported an emergent robust and almost perfect 2d Fermi surface nesting, and in the second work, elucidated the general mechanism of domain wall states in this material, deriving a general condition for domain wall states in bilayer graphene in terms of the underlying stacking potentials. The potential for “moire materials” as platforms for ultrafast control over electronic structure appears to be very rich indeed, and to this end we embarked on an investigation of ultrafast control in 2d materials. In two papers, concerning graphene and the dichalcogenide WSe 2 we reported the creation of laser controlled currents in graphene as well as control over momentum space excitation (a generalization of spin-valley coupling) in the dichalcogenide WSe2. In a further paper we explored various materials in a quest to understand further the role of laser induced dynamics at early times, and how this physics may be reliably probed in experiment.
Projektbezogene Publikationen (Auswahl)
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Perfect and Controllable Nesting in Minimally Twisted Bilayer Graphene. Nano Letters, 20(2), 971-978.
Fleischmann, Maximilian; Gupta, Reena; Wullschläger, Florian; Theil, Simon; Weckbecker, Dominik; Meded, Velimir; Sharma, Sangeeta; Meyer, Bernd & Shallcross, Samuel
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Ab initio study of ultrafast charge dynamics in graphene. Physical Review B, 103(8).
Li, Q. Z.; Elliott, P.; Dewhurst, J. K.; Sharma, S. & Shallcross, S.
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Angular momentum redistribution in laser-induced demagnetization. Physical Review B, 104(5).
Dewhurst, J. K.; Shallcross, S.; Elliott, P.; Eisebitt, S.; Schmising, C. v. Korff & Sharma, S.
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General relation between stacking order and Chern index: A topological map of minimally twisted bilayer graphene. Physical Review B, 104(12).
Theil, S.; Fleischmann, M.; Gupta, R.; Rost, F.; Wullschläger, F.; Sharma, S.; Meyer, B. & Shallcross, S.
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Ab initio study of ultrafast spin dynamics in Gdx(FeCo)1−x alloys. Applied Physics Letters, 120(4).
Dewhurst, J. K.; Shallcross, S.; Radu, I.; Elliott, P.; Korff, Schmising C. v. & Sharma, S.
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Computational analysis of transient XMCD sum rules for laser pumped systems: When do they fail?. Applied Physics Letters, 120(6).
Sharma, S.; Shallcross, S.; Elliott, P.; Eisebitt, S.; Schmising, C. von Korff & Dewhurst, J. K.
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Electronic origin of x-ray absorption peak shifts. Physical Review B, 106(6).
Shallcross, S.; Schmising, C. v. Korff; Elliott, P.; Eisebitt, S.; Dewhurst, J. K. & Sharma, S.
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Ultrafast optical control over spin and momentum in solids. Applied Physics Letters, 120(3).
Shallcross, S.; Li, Q. Z.; Dewhurst, J. K.; Sharma, S. & Elliott, P.
