Anomalous compressibility in 1T' MoTe2 single crystal: High-pressure Raman and structural studies

A detailed high-pressure study is carried out on 1T' MoTe2 using X-ray diffraction (XRD) and Raman spectroscopy measurements up to about 30.5 GPa. High-pressure XRD measurements show no structural transition. All the lattice parameters exhibit anomalous changes in the pressure region 8.4 to 12.7 GPa. The compressibility of the sample is found to be reduced by almost four times above 12.7 GPa with respect to that below 8.4 GPa. The anomalies in the Raman mode corresponding to the out of plane vibrations of Mo atoms sitting in the unit cell surface indicate a strong electron-phonon coupling possibly mediated by differential strain inside the unit cell. The high-pressure resistivity measurement at room temperature shows a rapid decrease in resistivity with increasing pressure up to 8 GPa with respect to the variation at higher pressure.