Cubic interactions and quantum criticality in dimerized antiferromagnets

L. Fritz, R. L. Doretto, S. Wessel, S. Wenzel, S. Burdin, and M. Vojta
Phys. Rev. B 83, 174416 – Published 6 May 2011

Abstract

In certain Mott-insulating dimerized antiferromagnets, triplet excitations of the paramagnetic phase display both three-particle and four-particle interactions. When such a magnet undergoes a quantum phase transition into a magnetically ordered state, the three-particle interaction becomes part of the critical theory provided that the lattice ordering wave vector is zero. One microscopic example is the staggered-dimer antiferromagnet on the square lattice, for which deviations from O(3) universality have been reported in numerical studies. Using both symmetry arguments and microscopic calculations, we show that a nontrivial cubic term arises in the relevant order-parameter quantum field theory, and we assess its consequences using a combination of analytical and numerical methods. We also present finite-temperature quantum Monte Carlo data for the staggered-dimer antiferromagnet which complement recently published results. The data can be consistently interpreted in terms of critical exponents identical to that of the standard O(3) universality class, but with anomalously large corrections to scaling. We argue that the cubic interaction of critical triplons, although irrelevant in two spatial dimensions, is responsible for the leading corrections to scaling due to its small scaling dimension.

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  • Received 26 January 2011

DOI:https://doi.org/10.1103/PhysRevB.83.174416

©2011 American Physical Society

Authors & Affiliations

L. Fritz1, R. L. Doretto2, S. Wessel3,4, S. Wenzel5, S. Burdin6, and M. Vojta7

  • 1Institut für Theoretische Physik, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany
  • 2Instituto de Física Teórica, Universidade Estadual Paulista, 01140-070 São Paulo, SP, Brazil
  • 3Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany
  • 4Institut für Theoretische Festkörperphysik, RWTH Aachen, Otto-Blumenthal-Strasse 26, D-52056 Aachen, Germany
  • 5Institute of Theoretical Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
  • 6Condensed Matter Theory Group, LOMA, UMR 5798, Université de Bordeaux I, F-33405 Talence, France
  • 7Institut für Theoretische Physik, Technische Universität Dresden, D-01062 Dresden, Germany

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Issue

Vol. 83, Iss. 17 — 1 May 2011

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