Infrared optical properties of the spin-½ quantum magnet TiOCl
Journal
Physical Review B - Condensed Matter and Materials Physics
Journal Volume
69
Journal Issue
12
Pages
1251081-1251088
Date Issued
2004
Author(s)
Abstract
We report results on the electrodynamic response of TiOCl, a low-dimensional spin-½ quantum magnet that shows a spin gap formation for T < Tc1 = 67K. The Fano-like shape of a few selected infrared active phonons suggests an interaction between lattice vibrations and a continuum of low-frequency (spin) excitations. The temperature dependence of the phonon mode parameters extends over a broad temperature range well above Tc1, indicating the presence of an extended fluctuation regime. In the temperature interval between 200 K and Tc1, there is a progressive dimensionality crossover (from two to one), as well as a spectral weight shift from low towards high frequencies. This allows us to identify a characteristic energy scale of about 430 K, ascribed to a pseudo-spin-gap. © 2004 The American Physical Society.
SDGs
Type
journal article