Charge-Density-Wave Transitions of Dirac Fermions Coupled to Phonons
ORAL
Abstract
The spontaneous generation of charge-density-wave order in a Dirac fermion system via the natural mechanism of electron-phonon coupling is studied in the framework of the Holstein model on the honeycomb lattice. Using two independent and unbiased quantum Monte Carlo methods, the phase diagram as a function of temperature and coupling strength is determined. It features a quantum critical point as well as a line of thermal critical points. Finite-size scaling appears consistent with fermionic Gross-Neveu-Ising universality for the quantum phase transition, and bosonic Ising universality for the thermal phase transition. The critical temperature has a maximum at intermediate couplings. Our findings motivate experimental efforts to identify or engineer Dirac systems with sufficiently strong and tunable electron-phonon coupling.
*MH acknowledges support by the DFG through SFB 1170 ToCoTronics; CC and ZYM by the Ministry of Science and Technology of China through the National Key Research and Development Program (grant 2016YFA0300502), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB28000000), and the National Science Foundation of China (11574359); XYX by HKRGC (C6026-16W,16324216, 16307117).
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Presenters
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Chuang Chen
- Chinese Academy of Sciences (CAS), China
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences
- Institute of Physics, Chinese Academy of Science