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Title: X-ray scattering of the spin-Peierls transition and soft phonon behavior in TiOCl.

Abstract

No abstract prepared.

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
923713
Report Number(s):
ANL/XSD/JA-60984
Journal ID: ISSN 0163-1829; PRBMDO; TRN: US0801881
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys. Rev. B; Journal Volume: 76; Journal Issue: 2007
Country of Publication:
United States
Language:
ENGLISH
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; PHONONS; SCATTERING; PHYSICS

Citation Formats

Abel, E. T., Matan, K., Chou, F. C., Isaacs, E. D., Moncton, D. E., Sinn, H., Alatas, A., Lee, Y. S., Massachusetts Inst. of Tech., and National Taiwan Univ. X-ray scattering of the spin-Peierls transition and soft phonon behavior in TiOCl.. United States: N. p., 2007. Web. doi:10.1103/PhysRevB.76.214304.
Abel, E. T., Matan, K., Chou, F. C., Isaacs, E. D., Moncton, D. E., Sinn, H., Alatas, A., Lee, Y. S., Massachusetts Inst. of Tech., & National Taiwan Univ. X-ray scattering of the spin-Peierls transition and soft phonon behavior in TiOCl.. United States. doi:10.1103/PhysRevB.76.214304.
Abel, E. T., Matan, K., Chou, F. C., Isaacs, E. D., Moncton, D. E., Sinn, H., Alatas, A., Lee, Y. S., Massachusetts Inst. of Tech., and National Taiwan Univ. Mon . "X-ray scattering of the spin-Peierls transition and soft phonon behavior in TiOCl.". United States. doi:10.1103/PhysRevB.76.214304.
@article{osti_923713,
title = {X-ray scattering of the spin-Peierls transition and soft phonon behavior in TiOCl.},
author = {Abel, E. T. and Matan, K. and Chou, F. C. and Isaacs, E. D. and Moncton, D. E. and Sinn, H. and Alatas, A. and Lee, Y. S. and Massachusetts Inst. of Tech. and National Taiwan Univ.},
abstractNote = {No abstract prepared.},
doi = {10.1103/PhysRevB.76.214304},
journal = {Phys. Rev. B},
number = 2007,
volume = 76,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • 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 T{sub c1}=66 K and have an incommensurate lattice distortion between T{sub c1} and T{sub c2}=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 T{sub c2}. The behavior of the phonons has been studied using inelastic x-ray scattering withmore » {approx}2 meV energy resolution. For the first time, a zone-boundary phonon which softens at the spin-Peierls temperature T{sub SP} has been observed. Our results show reasonably good quantitative agreement with the Cross-Fisher [Phys. Rev. B. 19, 402 (1979)] theory for the phonon dynamics at wave vectors near the zone boundary and temperatures near T{sub SP}. However, not all aspects of the data can be described, such as the strong overdamping of the soft mode above T{sub SP}. 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 T{sub SP}=T{sub c2}=92 K.« less
  • Comprehensive neutron-scattering studies were carried out on a series of high-quality single crystals of Cu{sub 1{minus}x}Zn{sub x}GeO{sub 3}. The Zn concentration x was determined for each sample using electron probe microanalysis. The measured Zn concentrations were found to be 40{endash}80{percent} lower than the target values. Nevertheless, the measured concentrations cover a wide range which enables a systematic study of the effects due to Zn doping. We have confirmed the coexistence of spin-Peierls (SP) and antiferromagnetic (AF) orderings at low temperatures and the measured phase diagram is presented. Most surprisingly, long-range AF ordering occurs even in the lowest available Zn concentrationmore » x=0.42{percent}, which places important constraints on theoretical models of the AF-SP coexistence. Magnetic excitations are also examined in detail. The AF excitations are sharp at low energies and show no considerable broadening as x increases, indicating that the AF ordering remains long ranged for x up to 4.7{percent}. On the other hand, the SP phase exhibits increasing disorder as x increases, as shown from the broadening of the SP excitations as well as the dimer reflection peaks. {copyright} {ital 1997} {ital The American Physical Society}« less
  • In this work we present the results of an inelastic x-ray scattering experiment detailing the behavior of the transverse acoustic [110] phonon in BaFe{sub 2}As{sub 2} as a function of temperature. When cooling through the structural transition temperature, the transverse acoustic phonon energy is reduced from the value at room temperature, reaching a maximum shift near inelastic momentum transfer q = 0.1. This softening of the lattice results in a change of the symmetry from tetragonal to orthorhombic at the same temperature as the transition to long-range antiferromagnetic order. While the lattice distortion is minor, the anisotropy in the magneticmore » exchange constants in pnictide parent compounds is large. We suggest mechanisms of electron-phonon coupling to describe the interaction between the lattice softening and the onset of magnetic ordering.« less
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