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TT: Fachverband Tiefe Temperaturen
TT 56: Correlated Electrons: Quantum-Critical Phenomena
TT 56.11: Vortrag
Donnerstag, 19. März 2020, 12:15–12:30, HSZ 304
Doping a dynamically generated quantum spin Hall insulator — •Zhenjiu Wang1, Toshihiro Sato1, Yuhai Liu2, Martin Hohenadler1, Wenan Guo2,3, and Fakher F. Assaad1 — 1Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Germany — 2Beijing Computational ScienceResearch Center, Beijing 100193, China — 3Department of Physics, Beijing Normal University, Beijing 100875, China
We consider a quantum spin Hall (QSH) insulator in which the spin-orbit coupling is dynamically generated by spontaneous symmetry breaking of the SU(2) spin symmetry. At the particle-hole symmetric point tuning the band-width leads to a direct and continuous quantum phase transition to an s-wave superconductor. This transition has an emergent Lorentz symmetry and is described by the theory of de-confined quantum criticality with emergent charged U(1) gauged spinons [1]. Here we will doped the QSH insulator by tuning the chemical potential. We observe a continuous quantum phase transition again to an s-wave superconductor. Such a phase transition has no emergent Lorentz invariance and fractionalized particles. In particular the dynamical exponent takes the value z=2 and one observes pronounced long-wavelength Goldstone modes. The above stems from auxiliary field quantum Monte Carlo simulations of a designer model, that, by definition, is free of the negative sign problem.
[1] Yuhai Liu, Zhenjiu Wang, Toshihiro Sato, Martin Hohenadler, Chong Wang, Wenan Guo, and Fakher F. Assaad, Nature Communications 10 (2019), no. 1, 2658.