Deconfined quantum critical point in fermionic systems

We consider a microscopic interacting model of spin-1/2 fermions on the honeycomb lattice [1] and study its quantum phase diagram by sign-problem-free Quantum Monte Carlo simulations. Our large-scale simulations show that there is a quantum phase transition between the Neel state and Kekule valence-bond-solid (VBS) phase. Remarkably, we find convincing evidences that this quantum phase transition is continuous, featuring a deconfined quantum critical point (DQCP) that is beyond the conventional Landau-Ginzburg-Wilson (LGW) paradigm [2]. We further compare this DQCP in fermionic systems with the bosonic DQCP in quantum spin models. Our study could pave a new avenue to understand exotic quantum phase transition beyond the conventional LGW paradigm.

[1] Zi-Xiang Li, Yi-Fan Jiang, Shao-Kai Jian, and Hong Yao, Nature Communications 8, 314 (2017).
[2] Zi-Xiang Li and Hong Yao, to appear.