The effects of disorder in dimerized quantum magnets in mean field approximations

Abstract

We study theoretically the effects of disorder on Bose-Einstein condensates (BEC) of bosonic triplon quasiparticles in doped dimerized quantum magnets. The condensation occurs in a strong enough magnetic field Hc, where the concentration of bosons in the random potential is sufficient to form the condensate. The effect of doping is partly modeled by delta - correlated disorder potential, which (i) leads to the uniform renormalization of the system parameters and (ii) produces disorder in the system with renormalized parameters. These approaches can explain qualitatively the available magnetization data in the Tl_(1-x)K_(x)CuCl_3 compound taken as an example. In addition to the magnetization, we found that the speed of the Bogoliubov mode has a peak as a function of doping parameter, x. No evidence of the pure Bose glass phase has been obtained in the BEC regime.

Includes 19 pages, 5 figures

References in corpus (12)

• Bose-Einstein Condensation in Magnetic Insulators
• Cold Bosons in Optical Lattices
• Cold atoms in the presence of disorder
• Bose glass and Mott glass of quasiparticles in a doped quantum magnet
• Bose-Einstein-condensed systems in random potentials
• Representative statistical ensembles for Bose systems with broken gauge symmetry
• Bogoliubov Excitations of Disordered Bose-Einstein Condensates
• Bose-Einstein-condensed gases in arbitrarily strong random potentials
• Pressure-Induced Magnetic Quantum Phase Transition in Gapped Spin System KCuCl3
• U(1)-Symmetry breaking and violation of axial symmetry in TlCuCl3 and other insulating spin systems
• Softening of Magnetic Excitations Leading to Pressure-Induced Quantum Phase Transition in Gapped Spin System KCuCl${}_3$
• The fraction of Bose-Einstein condensed triplons in TlCuCl3 from magnetization M(T,H)-data

Cited by in corpus (8)

• Dirty-boson physics with magnetic insulators
• Criticality in a disordered quantum antiferromagnet by neutron diffraction
• Bose - Einstein condensation of triplons with a weakly broken U(1) symmetry
• Criticality and scaling corrections for two-dimensional Heisenberg models in plaquette patterns with strong and weak couplings
• Gr{ü}neisen parameter of quantum magnets with spin gap
• Effects of exchange and weak Dzyaloshinsky-Moriya anisotropies on thermodynamic characteristics of spin-gapped magnets
• Phase Transitions in Three-Dimensional Bosonic Systems in Optical Lattices
• Hugenholtz -- Pines relations and the critical temperature of a Rabi coupled binary Bose system