Soft acoustic mode in thallium arsenic sulphide Tl3AsS4: I.J. Fritz,Sandia National Laboratories Albuquerque,NM 87185, U.S.A.; M. Gottlieb and T.J. Isaacs,Westinghouse Research Laboratories,Pittsburg, PA 15235, U.S.A.; and B. Morosin,Sandia National Laboratories,Albuquerque, NM 87185, U.S.A. |