Spin-orbiton and quantum criticality in FeSc2S4
Abstract
In FeSc2S4 spin-orbital exchange competes with strong spin-orbit coupling, suppressing long-range spin and orbital order and, hence, this material represents one of the rare examples of a spin-orbital liquid ground state. Moreover, it is close to a quantum-critical point separating the ordered and disordered regimes. Using THz and FIR spectroscopy we study low-lying excitations in FeSc2S4 and provide clear evidence for a spin-orbiton, an excitation of strongly entangled spins and orbitals. It becomes particularly well pronounced upon cooling, when advancing deep into the quantum-critical regime. Moreover, indications of an underlying structureless excitation continuum are found, a possible signature of quantum criticality.
Keywords
Cite
@article{arxiv.1410.6459,
title = {Spin-orbiton and quantum criticality in FeSc2S4},
author = {L. Mittelstädt and M. Schmidt and Zhe Wang and F. Mayr and V. Tsurkan and P. Lunkenheimer and D. Ish and L. Balents and J. Deisenhofer and A. Loidl},
journal= {arXiv preprint arXiv:1410.6459},
year = {2015}
}
Comments
11 pages, 11 figures (including 4 pages and 5 figures in Supplemental Material). Revised version according to suggestions of referees. Phys. Rev. B (in press)