Pairing induced by CDW fluctuations: the case of superconductivity in TiSe<sub>2</sub>

ORAL

Abstract

We theoretically studied the modes and spectrum of fluctuations of the CDW in TiSe2 using a model that describes its CDW state as a result of the intrinsic excitonic instability in TiSe2. The charge carriers are electrons within the CDW-renormalized conduction band (CDW quasiparticles). A calculation of the effective action for the CDW fluctuations shows the presence of gapless phase modes and gapped amplitude modes. Upon integrating out these fluctuations, we find that the amplitude fluctuations induce attractive pairing between the CDW quasiparticles resulting in s-wave superconductivity. A subsequent mean-field phase diagram of both CDW and superconducting critical temperatures as a function of doping reveals a dome-shaped superconducting phase coexisting with CDW in the near-commensurate regime, in agreement with the experimental phase diagram.

*Singapore Ministry of Education through grant MOE2015-T2-2-059,
National Research Foundation of Singapore under its Medium-Sized Centre Programme

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Presenters

  • Chuan Chen

    • Department of Physics, National University of Singapore
    • National University of Singapore

Authors

  • Chuan Chen

    • Department of Physics, National University of Singapore
    • National University of Singapore

  • Antonio Helio Castro Neto

    • National University of Singapore
    • Department of Physics, National University of Singapore
    • Centre for Advanced 2D Materials, National University of Singapore

  • Vitor Pereira

    • Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546
    • National University of Singapore
    • Department of Physics, National University of Singapore
    • Centre for Advanced 2D Materials, National University of Singapore