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Metallic and Deconfined Quantum Criticality in Dirac Systems
Zi Hong Liu1, Matthias Vojta2, Fakher F Assaad1
1Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, 97074 Würzburg, Germany.
Physical Review Letters
|March 11, 2022
Summary
Researchers explored interacting Dirac fermions on a bilayer honeycomb lattice, discovering two distinct phase transitions. These transitions lead to novel semimetallic and insulating states with broken symmetries, potentially revealing new deconfined quantum critical points.
Area of Science:
- Condensed Matter Physics
- Quantum Materials
- Theoretical Physics
Background:
- Spin-orbital liquids are exotic states of matter with potential applications.
- Understanding interacting fermion systems is crucial for discovering new quantum phases.
- Bilayer honeycomb lattices provide a platform for rich electronic behaviors.
Purpose of the Study:
- Investigate the phase diagram of interacting Dirac fermions on a bilayer honeycomb lattice.
- Identify and characterize zero-temperature phase transitions driven by interaction strength.
- Explore the nature of emergent quantum critical points in this system.
Main Methods:
- Utilized large-scale auxiliary-field quantum Monte Carlo (QMC) simulations.
- Analyzed a model of interacting Dirac fermions with SO(3)×U(1) symmetry.
- Examined phase transitions as a function of increasing interaction strength.
Main Results:
- Observed a continuous transition from a semimetal to a gapped semimetallic phase with broken SO(3) symmetry.
- Identified a subsequent transition to an insulating phase with broken U(1) symmetry.
- QMC data suggest a continuous transition to the insulating phase, distinct from mean-field predictions.
Conclusions:
- The study reveals two distinct zero-temperature phase transitions in the interacting Dirac fermion model.
- The findings present a candidate for a new type of deconfined quantum critical point with gapless fermionic degrees of freedom.
- The results offer insights into the physics of spin-orbital liquids and strongly correlated electron systems.
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