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Title: Chiral liquid phase of simple quantum magnets

We study a T=0 quantum phase transition between a quantum paramagnetic state and a magnetically ordered state for a spin S=1 XXZ Heisenberg antiferromagnet on a two-dimensional triangular lattice. The transition is induced by an easy-plane single-ion anisotropy D. At the mean-field level, the system undergoes a direct transition at a critical D=D c between a paramagnetic state at D>D c and an ordered state with broken U(1) symmetry at Dc. We show that beyond mean field the phase diagram is very different and includes an intermediate, partially ordered chiral liquid phase. Specifically, we find that inside the paramagnetic phase the Ising (J z) component of the Heisenberg exchange binds magnons into a two-particle bound state with zero total momentum and spin. This bound state condenses at D>D c, before single-particle excitations become unstable, and gives rise to a chiral liquid phase, which spontaneously breaks spatial inversion symmetry, but leaves the spin-rotational U(1) and time-reversal symmetries intact. This chiral liquid phase is characterized by a finite vector chirality without long-range dipolar magnetic order. In our analytical treatment, the chiral phase appears for arbitrarily small J z because the magnon-magnon attraction becomes singular near the single-magnon condensation transition. This phase existsmore » in a finite range of D and transforms into the magnetically ordered state at some Dc. In conclusion, we corroborate our analytic treatment with numerical density matrix renormalization group calculations.« less
Authors:
 [1] ;  [2] ; ORCiD logo [3] ;  [4] ;  [5] ;  [6]
  1. The Univ. of Tennessee, Knoxville, TN (United States)
  2. Northeastern Univ., Boston, MA (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. Univ. of Utah, Salt Lake City, UT (United States)
  5. Univ. of Minnesota, Minneapolis, MN (United States)
  6. The Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Report Number(s):
LA-UR-17-22905
Journal ID: ISSN 2469-9950; PRBMDO; TRN: US1800673
Grant/Contract Number:
AC52-06NA25396; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 96; Journal Issue: 18; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Material Science
OSTI Identifier:
1414150
Alternate Identifier(s):
OSTI ID: 1407829