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Excitations from a Bose-Einstein condensate of magnons in coupled spin ladders

V. O. Garlea·A. Zheludev·T. Masuda·L. -P. regnault·E. Ressouche·B. Brenier·H. Manaka·J. -H. Chung·Y. Qiu·K. Habicht·K. Kiefer·M. Boehm
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Abstract

The weakly coupled quasi-one-dimensional spin ladder compound (CH$_3$)$_2$CHNH$_3$CuCl$_3$ is studied by neutron scattering in magnetic fields exceeding the critical field of Bose-Einstein condensation of magnons. Commensurate long-range order and the associated Goldstone mode are detected and found to be similar to those in a reference 3D quantum magnet. However, for the upper two massive magnon branches the observed behavior is totally different, culminating in a drastic collapse of excitation bandwidth beyond the transition point.

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V. O. Garlea, A. Zheludev, T. Masuda, L. -P. regnault, E. Ressouche, B. Brenier, H. Manaka, J. -H. Chung, Y. Qiu, K. Habicht, K. Kiefer, M. Boehm. 2007-04-19. Excitations from a Bose-Einstein condensate of magnons in coupled spin ladders. https://doi.org/10.1103/physrevlett.98.167202

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