Excitations in the quantum paramagnetic phase of the
  quasi-one-dimensional Ising magnet CoNb$_2$O$_6$ in a transverse field:
  Geometric frustration and quantum renormalization effects

Cabrera, I; Thompson, J; Coldea, R; Prabhakaran, D; Bewley, R; Guidi, T; Rodriguez-Rivera, J; Stock, C

Journal article

Excitations in the quantum paramagnetic phase of the quasi-one-dimensional Ising magnet CoNb$_2$O$_6$ in a transverse field: Geometric frustration and quantum renormalization effects

Abstract:: The quasi-one-dimensional (1D) Ising ferromagnet CoNb$_2$O$_6$ has recently been driven via applied transverse magnetic fields through a continuous quantum phase transition from spontaneous magnetic order to a quantum paramagnet, and dramatic changes were observed in the spin dynamics, characteristic of weakly perturbed 1D Ising quantum criticality. We report here extensive single-crystal inelastic neutron scattering measurements of the magnetic excitations throughout the three-dimensional (3D) Brillouin zone in the quantum paramagnetic phase just above the critical field to characterize the effects of the finite interchain couplings. In this phase, we observe that excitations have a sharp, resolution-limited line shape at low energies and over most of the dispersion bandwidth, as expected for spin-flip quasiparticles. We map the full bandwidth along the strongly dispersive chain direction and resolve clear modulations of the dispersions in the plane normal to the chains, characteristic of frustrated interchain couplings in an antiferromagnetic isosceles triangular lattice. The dispersions can be well parametrized using a linear spin-wave model that includes interchain couplings and further neighbor exchanges. The observed dispersion bandwidth along the chain direction is smaller than that predicted by a linear spin-wave model using exchange values determined at zero field, and this effect is attributed to quantum renormalization of the dispersion beyond the spin-wave approximation in fields slightly above the critical field, where quantum fluctuations are still significant.

Publication status:: Published

Actions

Email

Email this record

Send the bibliographic details of this record to your email address.

Your Email
Please enter the email address that the record information will be sent to.

-
Your message (optional)
Please add any additional information to be included within the email.
Cite

Cite this record

APA Style

Cabrera, I., Thompson, J., Coldea, R., Prabhakaran, D., Bewley, R., Guidi, T., Rodriguez-Rivera, J., & Stock, C. (2014). Excitations in the quantum paramagnetic phase of the quasi-one-dimensional Ising magnet CoNb$_2$O$_6$ in a transverse field: Geometric frustration and quantum renormalization effects. Phys. Rev. B, 90(1), 014418.

MLA Style

Cabrera, I., et al. “Excitations in the Quantum Paramagnetic Phase of The Quasi-One-Dimensional Ising Magnet CoNb$_2$O$_6$ in a Transverse Field: Geometric Frustration and Quantum Renormalization Effects.” Phys. Rev. B, vol. 90, no. 1, American Physical Society, 2014, p. 014418.

Chicago Style

Cabrera, I, J Thompson, R Coldea, D Prabhakaran, R Bewley, T Guidi, J Rodriguez-Rivera, and C Stock. 2014. “Excitations in the Quantum Paramagnetic Phase of The Quasi-One-Dimensional Ising Magnet CoNb$_2$O$_6$ in a Transverse Field: Geometric Frustration and Quantum Renormalization Effects.” Phys. Rev. B 90 (1): 014418.
Share
Print