Observation of lattice distortion in the low-dimensional quantum spin system TiOBr by synchrotron x-ray diffraction

TL;DR

This study investigates lattice distortions in the low-dimensional quantum spin system TiOBr using synchrotron x-ray diffraction, revealing superlattice reflections and a first-order transition at 27K linked to structural changes.

Contribution

It provides the first detailed analysis of lattice distortions and phase transition in TiOBr using synchrotron x-ray diffraction, comparing it with TiOCl.

Findings

Superlattice reflections observed at specific reciprocal lattice points.

First-order phase transition identified at 27K.

Lattice distortion linked to dimerization in the spin system.

Abstract

We report here on physical properties and lattice distortion in the new quasi-one-dimensional spin system TiOBr by x-ray diffraction experiment using synchrotoron radiation. Comparing the crystal structure between TiOBr and TiOCl, the difference of b-axis length plays a key role for physical properties in both systems. By using single crystal of TiOBr, superlattice reflections were observed at (0 1.5 0) and (0 2.5 0). The temperature dependence of superlattice reflections imply the first order transition at $T_{c1}$=27K. We analyzed the data using the simple dimerization model.