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Applied Physics A

, Volume 74, Supplement 1, pp s840–s842 | Cite as

Spin dynamics in the high-field phase of quantum-critical S =1/2 TlCuCl3

  • Ch. Rüegg
  • N. Cavadini
  • A. Furrer
  • K. Krämer
  • H.U. Güdel
  • P. Vorderwisch
  • H. Mutka

Abstract.

An external magnetic field suppresses the spin-energy gap in singlet ground state S=1/2 TlCuCl3. The system becomes quantum-critical at Hc≈5.7 T, where the energy of the lowest Zeeman-split triplet excitation crosses the nonmagnetic ground state. Antiferromagnetic ordering is reported above Hc, which underlines the three-dimensional nature of the observed quantum phase transition. The intrinsic parameters of S=1/2 TlCuCl3 allow us to access the critical region microscopically by neutron scattering. A substantial study of the spin dynamics in the high-field phase of TlCuCl3 at T=1.5 K up to H=12 T was performed for the first time. The results possibly indicate two dynamical regimes, which can be understood within characteristically renormalized triplet modes and a low-lying dynamics of potentially collective origin.

PACS: 75.10.Jm; 75.40.Gb; 78.70.Nx 

Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • Ch. Rüegg
    • 1
  • N. Cavadini
    • 1
  • A. Furrer
    • 1
  • K. Krämer
    • 2
  • H.U. Güdel
    • 2
  • P. Vorderwisch
    • 3
  • H. Mutka
    • 4
  1. 1.Laboratory for Neutron Scattering, ETHZ & PSI, 5232 Villigen, SwitzerlandCH
  2. 2.Department for Chemistry and Biochemistry, Universität Bern, 3000 Bern 9, SwitzerlandCH
  3. 3.Hahn-Meitner-Institut, BENSC, 14109 Berlin (Wannsee), GermanyDE
  4. 4.Institut Laue-Langevin, B.P. 156, 38042 Grenoble Cedex 9, FranceFR

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