Pairing symmetry of interacting fermions on a twisted bilayer graphene superlattice

By Huaiming Guo, Xingchuan Zhu, S. Feng, Richard Scalettar. Physical review B, 2018

135 citations recorded by the source corpus.

The pairing symmetry of an effective Hamiltonian for interacting fermions on a twisted bilayer graphene superlattice is studied with the determinant quantum Monte Carlo method. The model has the symmetry of a triangle lattice and a nearly-flat low energy band, features which underlie the magic-angle twisted bilayer graphene superlattice. We show that the low temperature phase is insulating at half-filling, even for relatively weak interactions. The natures of the spin and pairing correlations upon doping are determined, and exhibit an electron-hole asymmetry consistent with experiment. Among the pairing symmetries allowed, we demonstrate that the dominating channels are $d$-wave, opening the possibility of condensation into an unconventional $d_{x^2-y^2}+id_{xy}$ phase, which is characterized by an integer topological invariant and gapless edge states.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/fbb4d4d90572da1f9f3546e4694c6611d1a17af9

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atomic and Molecular Physics, and Optics

1. Ashvin Vishwanath
2. T. Senthil
3. Yi-Zhuang You
4. H. Po
5. Liujun Zou
6. A. Nahum
7. E. Witten
8. Chong Wang

In Materials Chemistry

1. Ashvin Vishwanath
2. Yi-Zhuang You
3. T. Senthil
4. H. Po
5. Liujun Zou
6. G. Tarnopolsky
7. Bogdan Andrei Bernevig
8. Jun-Woo Ahn

Citations in the corpus

• Superconductivity from valley fluctuations and approximate SO(4) symmetry in a weak coupling theory of twisted bilayer graphene (2018, background): “Although [27, 28, 33] also predicts topological superconductor from weak coupling/quantum Monte Carlo, their”
• Band structure of twisted bilayer graphene: Emergent symmetries, commensurate approximants, and Wannier obstructions (2018, background): “In the recent theoretical literature, some authors have proposed describing the system by a triangular lattice tight-binding model with 2 spins and 2 orbitals (presumably corresponding to the 2 valleys) per lattice site [4, 8, 12, 29].”