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arXiv · 1910.00723

Stochastic many-body perturbation theory for Moir\'e states in twisted bilayer phosphorene

Jacob Brooks·Guorong Weng·Stephanie Taylor·Vojtech Vlcek
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Abstract

A new implementation of stochastic many-body perturbation theory for periodic 2D systems is presented. The method is used to compute quasiparticle excitations in twisted bilayer phosphorene. Excitation energies are studied using stochastic $G_0W_0$ and partially self-consistent $\bar \Delta GW_0$ approaches. The approach is inexpensive; it is used to study twisted systems with unit cells containing $>2,700$ atoms ($>13,500$ valence electrons), which corresponds to a minimum twisting angle of $\approx 3.1^\circ$. Twisted bilayers exhibit band splitting, increased localization and formation of localized Moir\'e impurity states, as documented by band-structure unfolding. Structural changes in twisted structures lift band degeneracies. Energies of the impurity states vary with the twisting angle due to an interplay between non-local exchange and polarization effects. The mechanisms of quasiparticle energy (de)stabilization due to twisting are likely applicable to a wide range of low-dimensional Moir\'{e} superstructures.

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Jacob Brooks, Guorong Weng, Stephanie Taylor, Vojtech Vlcek. 2019-10-02. Stochastic many-body perturbation theory for Moir\'e states in twisted bilayer phosphorene. https://doi.org/10.1088/1361-648x/ab6d8c

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