1997/04/04 by D. C. Dender, P. R. Hammar, Daniel H. Reich +2 · 5 citations
Chemistry · Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Bethe ansatz #Chemistry #Condensed matter physics #Crystallography #Energy (signal processing) #Field (mathematics) #Geometry #Mathematical physics #Orientation (vector space) #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Scattering #Spin (aerodynamics) #Theoretical and Computational Physics #Thermodynamics #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.79.1750
11 pages, 5 postscript figures, LaTeX, Submitted to PRL 3/31/97, e-mail comments to [email protected]
arxiv created 1997/04/04 · openalex publication_date 1997/09/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
Neutron scattering from copper benzoate, Cu(C6D5COO)2\ifmmode \else \.\fi3D2O, provides the first direct experimental evidence for field-dependent incommensurate low energy modes in a one-dimensional spin S\phantom\rule0ex0ex=\phantom\rule0ex0ex1/2 antiferromagnet. Soft modes occur for wave vectors \stackrel\ifmmode \else \~\fiq\phantom\rule0ex0ex=\phantom\rule0ex0ex\ensuremathπ\ifmmode±\else\textpm\fi\ensuremathδ\stackrel\ifmmode \else \~\fiq(H), where \ensuremathδ\stackrel\ifmmode \else \~\fiq(H)\ensuremath≈2\ensuremathπM(H)/g\ensuremathμB as predicted by Bethe ansatz and spinon descriptions of the S\phantom\rule0ex0ex=\phantom\rule0ex0ex1/2 chain. Unexpected was a field-induced energy gap \ensuremathΔ(H)\ensuremath∝H^\ensuremathα, where \ensuremathα\phantom\rule0ex0ex=\phantom\rule0ex0ex0.65(3) as determined from specific heat measurements. At H\phantom\rule0ex0ex=\phantom\rule0ex0ex7T ( g\ensuremathμBH/J\phantom\rule0ex0ex=\phantom\rule0ex0ex0.52), the magnitude of the gap varies from 0.06Jto0.3J depending on the orientation of the applied field.