Charge-Density-Wave Transitions of Dirac Fermions Coupled to Phonons

Chuang Chen, Xiao Yan Xu, Zi Yang Meng, and Martin Hohenadler

Phys. Rev. Lett. 122, 077601 – Published 19 February 2019

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.

Received 1 October 2018

DOI:https://doi.org/10.1103/PhysRevLett.122.077601

Physics Subject Headings (PhySH)

Charge density waves Electron-phonon coupling Metal-insulator transition Phase diagrams Phase transitions Quantum phase transitions

Graphene

Quantum Monte Carlo

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Chuang Chen^1,2, Xiao Yan Xu³, Zi Yang Meng^1,4,5, and Martin Hohenadler⁶

¹Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
²School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
³Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
⁴CAS Center of Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
⁵Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
⁶Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074 Würzburg, Germany

Charge Order in the Holstein Model on a Honeycomb Lattice

Y.-X. Zhang, W.-T. Chiu, N. C. Costa, G. G. Batrouni, and R. T. Scalettar

Phys. Rev. Lett. 122, 077602 (2019)

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Issue

Vol. 122, Iss. 7 — 22 February 2019

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