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arXiv · 1006.0584

Bose Glass-BEC Transition of Magnons in Tl$_{1-x}$K$_x$CuCl$_3$

Fumiko Yamada·Hidekazu Tanaka·Toshio Ono·Hiroyuki Nojiri
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Abstract

We report the magnetic-field induced Bose glass$-$BEC transition of magnons in Tl$_{1-x}$K$_x$CuCl$_3$ and its critical behavior investigated through specific heat and ESR measurements. The field dependence of the BEC transition temperature $T_{\rm N}$ can be described by the power law $\left[H\,{-}\,H_{\rm c}\right]\,{\propto}\,T_{\rm N}^ϕ$ near the quantum critical point $H_{\rm c}\,{\sim}\,3.5$ T. The critical exponent $ϕ$ tends to reach a value smaller than 1/2 with decreasing fitting window in contrast with $ϕ\rightarrow 3/2$ for the standard BEC in pure system. At sufficiently low temperatures, the ESR line shape for $H\,{\simeq}\,H_{\rm c}$ is intermediate between Gaussian and Lorentzian. This indicates the localization of magnons for $H\,{<}H_{\rm c}$ at T=0.

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Fumiko Yamada, Hidekazu Tanaka, Toshio Ono, Hiroyuki Nojiri. 2010-06-03. Bose Glass-BEC Transition of Magnons in Tl$_{1-x}$K$_x$CuCl$_3$. https://arxiv.org/abs/1006.0584

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