• DOI:10.1007/s11433-021-1862-3
• Corpus ID: 239049730

Unprotected quadratic band crossing points and quantum anomalous Hall effect in FeB2 monolayer

@article{Wu2022UnprotectedQB,
  title={Unprotected quadratic band crossing points and quantum anomalous Hall effect in FeB2 monolayer},
  author={Dongyu Wu and Yun-Peng Huang and Song-Gen Sun and Jiacheng Gao and Zhaopeng Guo and Hongming Weng and Zhongyuan Fang and Kun Jiang and Zhijun Wang},
  journal={Science China Physics, Mechanics \& Astronomy},
  year={2022}
}

• Dongyu Wu, Yun-Peng Huang, +6 authors Zhijun Wang
• Published 21 October 2021
• Physics
• Science China Physics, Mechanics & Astronomy

Quadratic band crossing points (QBCPs) and quantum anomalous Hall effect (QAHE) have attracted the attention of both theoretical and experimental researchers in recent years. Based on first-principle calculations, we find that the FeB 2 monolayer is a nonmagnetic semimetal with QBCPs at K . Through symmetry analysis and k · p invariant theory, we find that the QBCP is not protected by rotation symmetry and consists of two Dirac points with same chirality (Berry phase of 2 π ). Once introducing Coulomb interactions, we find that there is a spontaneous-time-reversal-breaking instability of the spinful QBCPs, which gives rise to a C = 2 QAH insulator with orbital moment ordering.