Dynamical Dzyaloshinsky-Moriya interaction in KCuF3: Raman evidence for an antiferrodistortive lattice instability

Autor:	Gnezdilov, V., Deisenhofer, J., Lemmens, P., Wulferding, D., Afanasiev, O., Ghigna, P., Loidl, A., Yeremenko, A.
Rok vydání:	2010
Předmět:	Condensed Matter - Strongly Correlated Electrons Condensed Matter - Materials Science
Zdroj:	Journ. Low Temperature Physics 38, 538 (2012)
Druh dokumentu:	Working Paper
Popis:	In the orbitally ordered, quasi-one dimensional Heisenberg antiferromagnet KCuF3 the low-energy Eg and B1g phonon modes show an anomalous softening (25% and 13%) between room temperature and the characteristic temperature T_S = 50 K. In this temperature range a freezing-in of F ion dynamic displacements is proposed to occur. In addition, the Eg mode at about 260 cm-1 clearly splits below T_S. The width of the phonon lines above T_S follows an activated behavior with an activation energy of about 50 K. Our observations clearly evidence a reduction of the structural symmetry below T_S and indicate a strong coupling of lattice and spin fluctuations for T>T_S. Comment: 7 pages, 9 figures
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/1003.1666 Zobrazit plný text záznamu View this record from Arxiv