• 2019 가을학술논문발표회 및 임시총회(2019 KPS Fall Meeting)
  • 2019-10-23 - 2019-10-25

G2.06*

Quantum criticalities with lattice vibrations

한상은 1, 이준현 2, 문은국* 1

1한국과학기술원 물리학과, 2Condensed Matter Theory Center and Joint Quantum Institute, University of Maryland

egmoon@kaist.ac.kr

Abstract:

Quantum criticality is one of the most important concepts in modern condensed matter physics, as novel physics may arise in the vicinity of the quantum critical point by quantum fluctuations. These fluctuations inevitably couple to lattice vibrations in real materials due to the lattice structures. It is well understood that a class of thermal continuous transitions on lattices is eventually destabilized by either macroscopic instability of lattice structures or induced first-order symmetry breaking transitions. However, for the quantum phase transition, little is known about its consequences. Here, we demonstrate that such interplay between quantum criticality and lattice vibration leads to a new class of quantum many-particle phenomena. Moreover, we suggest a new stability condition for these criticalities which generalizes the Larkin-Pikin criterion of thermal transitions to a quantum version. Our results suggest a new direction to find novel quantum criticalities in nature. 

Keywords:

Quantum criticality, lattice vibration, phonon, quantum phase transition, Larkin-Pikin criteria, emergent symmetry