Optical Evidence for Symmetry Changes above the Néel Temperature of KCuF3

J. Deisenhofer, I. Leonov, M. V. Eremin, Ch. Kant, P. Ghigna, F. Mayr, V. V. Iglamov, V. I. Anisimov, and D. van der Marel
Phys. Rev. Lett. 101, 157406 – Published 10 October 2008

Abstract

We report on optical measurements of the 1D Heisenberg antiferromagnet KCuF3. The crystal-field excitations of the Cu2+ ions have been observed and their temperature dependence can be understood in terms of magnetic and exchange-induced dipole mechanisms and vibronic interactions. Above TN we observe a new temperature scale TS characterized by the emergence of narrow absorption features that correlate with changes of the orbital ordering as observed by Paolasini et al. [Phys. Rev. Lett. 88, 106403 (2002)]. The appearance of these optical transitions provides evidence for a symmetry change above the Néel temperature that affects the orbital ordering and paves the way for the antiferromagnetic ordering.

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  • Received 13 April 2007

DOI:https://doi.org/10.1103/PhysRevLett.101.157406

©2008 American Physical Society

Authors & Affiliations

J. Deisenhofer1, I. Leonov2, M. V. Eremin3, Ch. Kant4, P. Ghigna5, F. Mayr4, V. V. Iglamov3, V. I. Anisimov6, and D. van der Marel1

  • 1Département de Physique de la Matière Condensée, Université de Genève, CH-1211 Genève 4, Switzerland
  • 2Abdus Salam International Centre for Theoretical Physics, Trieste 34014, Italy
  • 3Kazan State University, 420008 Kazan, Russia
  • 4EP 5, EKM, Institute for Physics, Augsburg University, D-86135 Augsburg, Germany
  • 5Dipartimento di Chimica Fisica “M. Rolla,” Università di Pavia, I-27100 Pavia, Italy
  • 6Institute of Metal Physics, 620219 Yekaterinburg GSP-170, Russia

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Issue

Vol. 101, Iss. 15 — 10 October 2008

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