Temperature renormalization of the magnetic excitations in S = 1/2 KCuCl3

Cavadini, N.; Rüegg, Ch.; Henggeler, Wolfgang; Furrer, A.; Güdel, Hans-Ulrich; Krämer, Karl; Mutka, H. (2000). Temperature renormalization of the magnetic excitations in S = 1/2 KCuCl3. European physical journal. B - condensed matter and complex systems, 18(4), pp. 565-571. EDP Sciences 10.1007/s100510070003

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A complete temperature characterization of the spin dynamics in the unconventional S =1/2 antiferromagnet KCuCl3 is presented from single crystal inelastic neutron scattering studies. KCuCl3 features a quantum disordered singlet ground state with a finite spin gap to triplet excitations of dimer origin. Three dimensional magnetic correlations support the dispersive propagation of the excitations in the whole reciprocal space. Upon increasing the temperature, a renormalization in the energy, in the intensity and in the damping rate of the triplet modes is reported. The experimental observations can be described within the framework of a selfconsistent dimer RPA theory, with no free parameters. The driving mechanism behind the model is the thermally activated decrease of the occupation difference n 0 - n 1 between singlet and triplet dimer states. This is the expression of kinematic constraints which are of minor importance for classical magnons in Néel ordered antiferromagnets. Implications for the temperature dependence of macroscopic quantities are discussed.

Item Type:

Journal Article (Original Article)


08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)

UniBE Contributor:

Henggeler, Wolfgang, Güdel-Zahler, Hans-Ulrich, Krämer, Karl


500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry
500 Science > 530 Physics




EDP Sciences




Karl Krämer

Date Deposited:

18 Jan 2016 08:27

Last Modified:

02 Mar 2023 23:26

Publisher DOI:






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