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arXiv · 2012.09885

Strain-induced quantum phase transitions in magic angle graphene

Daniel E. Parker·Tomohiro Soejima·Johannes Hauschild·Michael P. Zaletel·Nick Bultinck
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Abstract

We investigate the effect of uniaxial heterostrain on the interacting phase diagram of magic-angle twisted bilayer graphene. Using both self-consistent Hartree-Fock and density-matrix renormalization group calculations, we find that small strain values ($ε\sim 0.1 - 0.2 \%$) drive a zero-temperature phase transition between the symmetry-broken Kramers intervalley-coherent insulator and a nematic semi-metal. The critical strain lies within the range of experimentally observed strain values, and we therefore predict that strain is at least partly responsible for the sample-dependent experimental observations.

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Daniel E. Parker, Tomohiro Soejima, Johannes Hauschild, Michael P. Zaletel, Nick Bultinck. 2020-12-17. Strain-induced quantum phase transitions in magic angle graphene. https://doi.org/10.1103/physrevlett.127.027601

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