Dresden 2009 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 6: Postersession Correlated Electrons: (General) Theory, Low-Dimensional Systems, Kondo Physics, Heavy Fermions, Quantum-Critical Phenomena

TT 6.66: Poster

Monday, March 23, 2009, 13:00–16:45, P1A

Quantum evolution from spin-gap to antiferromagnetic state in the frustrated J₁-J₂ system (CuCl_1−xBr_x)La(Nb_1−yTa_y)₂O₇ — •Vladimir Gnezdilov^1,2, Peter Lemmens², Kwang-Yong Choi³, and Hiroshi Kageyama⁴ — ¹ILTP, Kharkov, Ukraine — ²IPKM, TU Braunschweig, Germany — ³Chung-Ang Univ., Seoul, Korea — ⁴IC Kyoto, Japan

The (CuCl_1−xBr_x)La(Nb_1−yTa_y)₂O₇ frustrated system shows a quantum evolution from a spin-gap to an antiferromagnetic state [1] depending on composition x and y. Pronounced effects are observed in Raman spectra in dependence of x and y. Taking into account all previous experimental observations and models, our Raman data are used to identify a realistic coordinate environment of Cu²⁺ ions in the CuCl layers. Work supported by DFG and ESF-HFM.

[1]. Y. J. Uemyra et al., arXiv:0806.2021v1.