### Abstract

We show that a wide class of unconventional quantum criticality emerges when orbital currents cause quantum phase transitions from zero-gap semiconductors such as Dirac fermions to a topological insulator or a Chern insulator. Changes in Fermi-surface topology concomitant with [SU(2) or time-reversal] symmetry breakings generate quantum critical lines (QCLs) even beyond the quantum critical point. This QCL running at temperature T=0 separates two distinct topological phases. This is in contrast to the simple termination of the finite-temperature critical line at the quantum critical point without any extension of it at T=0. Topology change causes the unconventionality beyond the concept of simple spontaneous symmetry breaking assumed in the conventional Landau-Ginzburg-Wilson scenario. The unconventional universality implied by mean-field critical exponents β>1/2 and δ<3 is protected by the existence of the quantum critical line. It emerges for several specific lattice models including the honeycomb, kagome, diamond, and pyrochlore lattices. We also clarify phase diagrams of the topological phases in these lattices at finite temperatures.

Original language | English |
---|---|

Article number | 115143 |

Journal | Physical Review B - Condensed Matter and Materials Physics |

Volume | 88 |

Issue number | 11 |

DOIs | |

Publication status | Published - 2013 Sep 27 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics

### Cite this

*Physical Review B - Condensed Matter and Materials Physics*,

*88*(11), [115143]. https://doi.org/10.1103/PhysRevB.88.115143

**Phase diagram structure of topological Mott transition for zero-gap semiconductors beyond conventional Landau-Ginzburg-Wilson scenario.** / Kurita, Moyuru; Yamaji, Youhei; Imada, Masatoshi.

Research output: Contribution to journal › Article

*Physical Review B - Condensed Matter and Materials Physics*, vol. 88, no. 11, 115143. https://doi.org/10.1103/PhysRevB.88.115143

}

TY - JOUR

T1 - Phase diagram structure of topological Mott transition for zero-gap semiconductors beyond conventional Landau-Ginzburg-Wilson scenario

AU - Kurita, Moyuru

AU - Yamaji, Youhei

AU - Imada, Masatoshi

PY - 2013/9/27

Y1 - 2013/9/27

N2 - We show that a wide class of unconventional quantum criticality emerges when orbital currents cause quantum phase transitions from zero-gap semiconductors such as Dirac fermions to a topological insulator or a Chern insulator. Changes in Fermi-surface topology concomitant with [SU(2) or time-reversal] symmetry breakings generate quantum critical lines (QCLs) even beyond the quantum critical point. This QCL running at temperature T=0 separates two distinct topological phases. This is in contrast to the simple termination of the finite-temperature critical line at the quantum critical point without any extension of it at T=0. Topology change causes the unconventionality beyond the concept of simple spontaneous symmetry breaking assumed in the conventional Landau-Ginzburg-Wilson scenario. The unconventional universality implied by mean-field critical exponents β>1/2 and δ<3 is protected by the existence of the quantum critical line. It emerges for several specific lattice models including the honeycomb, kagome, diamond, and pyrochlore lattices. We also clarify phase diagrams of the topological phases in these lattices at finite temperatures.

AB - We show that a wide class of unconventional quantum criticality emerges when orbital currents cause quantum phase transitions from zero-gap semiconductors such as Dirac fermions to a topological insulator or a Chern insulator. Changes in Fermi-surface topology concomitant with [SU(2) or time-reversal] symmetry breakings generate quantum critical lines (QCLs) even beyond the quantum critical point. This QCL running at temperature T=0 separates two distinct topological phases. This is in contrast to the simple termination of the finite-temperature critical line at the quantum critical point without any extension of it at T=0. Topology change causes the unconventionality beyond the concept of simple spontaneous symmetry breaking assumed in the conventional Landau-Ginzburg-Wilson scenario. The unconventional universality implied by mean-field critical exponents β>1/2 and δ<3 is protected by the existence of the quantum critical line. It emerges for several specific lattice models including the honeycomb, kagome, diamond, and pyrochlore lattices. We also clarify phase diagrams of the topological phases in these lattices at finite temperatures.

UR - http://www.scopus.com/inward/record.url?scp=84884827165&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84884827165&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.88.115143

DO - 10.1103/PhysRevB.88.115143

M3 - Article

AN - SCOPUS:84884827165

VL - 88

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 0163-1829

IS - 11

M1 - 115143

ER -