HIGH-PRESSURE RAMAN-STUDY OF THE CHAIN CHALCOGENIDE TLINTE2

The effect of pressure on the Raman spectra of the “chain” compound TlInTe2 is investigated up to 17 GPa and at room temperature using a diamond anvil cell. Three Raman peaks are observed in the low pressure tetragonal phase. The pressure coefficients and the corresponding mode Grüneisen parameters γ of their frequencies are obtained. The modes are tentatively assigned by comparison to Raman spectra of related TISe‐type compounds. The frequency dependence of γ indicates that a hierarchy of bonding forces is present. The appearance and disappearance of a new Raman peak at about 1.75 GPa is probably due to a gradual, pressure induced mutual replacement of In atoms by Tl atoms and does not indicate the occurence of a structural phase transition. Near 7.0 GPa a phase transition occurs, while at even higher pressures indications for a second phase transition are found. Copyright © 1990 WILEY‐VCH Verlag GmbH & Co. KGaA