Speaker
Description
Interaction-induced quantum phase transitions in Dirac materials, known as relativistic Mott transitions, involve spontaneous symmetry breaking and are accompanied by a non-vanishing expectation value of a scalar order parameter. For the first time, such transitions have recently been observed experimentally in moiré Dirac materials through the tuning of the twist angle. In this contribution, we explore the chiral Ising, chiral XY, and chiral Heisenberg models at zero and finite temperature using the functional renormalization group. We show the emergence of the quantum critical fan, which allows the observation of quantum critical behavior even at finite temperatures, and facilitating thus its experimental and numerical detection. Our approach furthermore allows us to systematically describe semimetallic precondensation and the manifestation of the Mermin-Wagner theorem at finite temperature. In addition, we discuss signatures of non-Dirac-liquid behavior, analogous to non-Fermi-liquid physics near metallic quantum critical points, as well as signatures of Berezinskii-Kosterlitz-Thouless physics in the chiral XY model, connecting our work to topological phase transitions. Finally, we study the emergence of Lorentz invariance near and away from criticality, and show how the recent experimental results can be described by our approach.
| Affiliation | Ruhr University Bochum |
|---|---|
| Career status | Postdoc |