The phase diagram of isotropically expanded graphene cannot be correctly predicted by ignoring either electron correlations, or mobile carbons, or the effect of applied stress, as was done so far. We calculate the ground state enthalpy (not just energy) of strained graphene by an accurate off-lattice quantum Monte Carlo correlated ansatz of great variational flexibility. Following undistorted semimetallic graphene at low strain, multideterminant Heitler-London correlations stabilize between ≃8.5% and ≃15% strain an insulating Kekulé-like dimerized (DIM) state. Closer to a crystallized resonating-valence bond than to a Peierls state, the DIM state prevails over the competing antiferromagnetic insulating state favored by density-functional calculations which we conduct in parallel. The DIM stressed graphene insulator, whose gap is predicted to grow in excess of 1 eV before failure near 15% strain, is topological in nature, implying under certain conditions 1D metallic interface states lying in the bulk energy gap.

Correlation-Driven Dimerization and Topological Gap Opening in Isotropically Strained Graphene / Sorella, Sandro; Seki, Kazuhiro; Brovko, Oleg O.; Shirakawa, Tomonori; Miyakoshi, Shohei; Yunoki, Seiji; Tosatti, Erio. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 121:6(2018), pp. 1-6. [10.1103/PhysRevLett.121.066402]

Correlation-Driven Dimerization and Topological Gap Opening in Isotropically Strained Graphene

Sorella, Sandro
Membro del Collaboration group
;
Seki, Kazuhiro
Membro del Collaboration group
;
Shirakawa, Tomonori
Membro del Collaboration group
;
Yunoki, Seiji
Membro del Collaboration group
;
Tosatti, Erio
Membro del Collaboration group
2018

Abstract

The phase diagram of isotropically expanded graphene cannot be correctly predicted by ignoring either electron correlations, or mobile carbons, or the effect of applied stress, as was done so far. We calculate the ground state enthalpy (not just energy) of strained graphene by an accurate off-lattice quantum Monte Carlo correlated ansatz of great variational flexibility. Following undistorted semimetallic graphene at low strain, multideterminant Heitler-London correlations stabilize between ≃8.5% and ≃15% strain an insulating Kekulé-like dimerized (DIM) state. Closer to a crystallized resonating-valence bond than to a Peierls state, the DIM state prevails over the competing antiferromagnetic insulating state favored by density-functional calculations which we conduct in parallel. The DIM stressed graphene insulator, whose gap is predicted to grow in excess of 1 eV before failure near 15% strain, is topological in nature, implying under certain conditions 1D metallic interface states lying in the bulk energy gap.
121
6
1
6
066402
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.121.066402
https://arxiv.org/abs/1804.04479
Sorella, Sandro; Seki, Kazuhiro; Brovko, Oleg O.; Shirakawa, Tomonori; Miyakoshi, Shohei; Yunoki, Seiji; Tosatti, Erio
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/87957
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