X-ray Scattering Study of the spin-Peierls transition and soft phonon behavior in TiOCl

Abstract

We have studied the S=1/2 quasi-one-dimensional antiferromagnet TiOCl using single crystal x-ray diffraction and inelastic x-ray scattering techniques. The Ti ions form staggered spin chains which dimerize below Tc1 = 66 K and have an incommensurate lattice distortion between Tc1 and Tc2 = 92 K. Based on our measurements of the intensities, wave vectors, and harmonics of the incommensurate superlattice peaks, we construct a model for the incommensurate modulation. The results are in good agreement with a soliton lattice model, though some quantitative discrepancies exist near Tc2. The behavior of the phonons has been studied using inelastic x-ray scattering with ~2 meV energy resolution. For the first time, a zone boundary phonon which softens at the spin-Peierls temperature Tsp has been observed. Our results show reasonably good quantitative agreement with the Cross-Fisher theory for the phonon dynamics at wave vectors near the zone boundary and temperatures near Tsp. However, not all aspects of the data can be described, such as the strong overdamping of the soft mode above Tsp. Overall, our results show that TiOCl is a good realization of a spin-Peierls system, where the phonon softening allows us to identify the transition temperature as Tsp=Tc2=92 K

14 pages, 14 figures

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• Commensurate Fluctuations in the Pseudogap and Incommensurate spin-Peierls Phases of TiOCl
• Roles of two successive phase transitions in new spin-Peierls system TiOBr

Cited by in corpus (23)

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• Magnetic structure and Dzyaloshinskii-Moriya interaction in the $S=1/2$ helical-honeycomb antiferromagnet $\alpha$-Cu${}_2$V${}_2$O${}_7$
• Materializing Rival Ground States in the Barlowite Family of Kagome Magnets: Quantum Spin Liquid, Spin Ordered, and Valence Bond Crystal States
• Two pressure-induced transitions in TiOCl: Mott insulator to anisotropic metal
• Electronic structure of the two-dimensional Heisenberg antiferromagnet VOCl: a multi-orbital Mott insulator
• The entanglement dynamics of the bipartite quantum system: toward entanglement sudden death
• Microscopic model for transitions from Mott to spin-Peierls insulator in TiOCl
• Probing the interplay between lattice dynamics and short-range magnetic correlations in CuGeO3 with femtosecond RIXS
• Can the Mott Insulator TiOCl be Metallized by Doping? A First-Principles Study
• High energy spin excitations in the quantum spin liquid candidate Zn-barlowite probed by resonant inelastic x-ray scattering
• Competing orders in the Dirac-like electronic structure and the non-linear sigma model with the topological terms
• Momentum-resolved single-particle spectral function for TiOCl from a combination of density functional and variational cluster calculations
• Critical properties of the unconventional spin-Peierls system TiOBr
• Suppression of the commensurate spin-Peierls state in Sc-doped TiOCl
• Microscopic theory for the incommensurate transition in TiOCl
• High pressure x-ray study of spin-Peierls physics in the quantum spin chain material TiOCl
• Pressure-driven phase transitions in correlated systems
• Heat conductivity of the spin-Peierls compounds TiOCl and TiOBr
• Absence of static magnetic order in lightly-doped Ti1-xScxOCl down to 1.7 K
• Theoretical study of the magnetism in the incommensurate phase of TiOCl
• Incommensurate spin Luttinger liquid phase in a model for the spin-Peierls materials TiOBr and TiOCl
• Relevance of nonadiabatic effects in TiOCl
• Pressure-induced Spin-Peierls to Incommensurate Charge-Density-Wave Transition in the Ground State of TiOCl