Chinese Acad Sci, Inst Phys, Beijing High Pressure Res Ctr, Beijing 100080, Peoples R China
; Jilin Univ, Dept Phys, Changchun 130023, Peoples R China
; Chinese Acad Sci, Inst High Energy Phys, Beijing High Pressure Res Ctr, Beijing 100039, Peoples R China
In situ high-pressure energy dispersive x-ray-diffraction measurements on polycrystalline powder of Ca2CuO3 with a Cu-O chain structure have been performed in a diamond-anvil cell (DAC) instrument using synchrotron radiation. The resistance versus pressure and capacitance versus pressure relationships up to 20 GPa have been studied simultaneously using the DAC technique at room temperature. The results showed that the structure of Ca2CuO3 is stable under pressures up to 34 GPa. According to the Birch-Murnaghan equation of state, assuming B-0(')=4, the bulk modulus B-0=165.4+/-1.8 GPa has been obtained. It is found that the resistance decreases continuously with increasing pressure up to 20 GPa, however, a sharp drop in the pressure range of 1.8similar to6 GPa is observed. Meanwhile the capacitance increases all along with the pressure and displays a steep jump at the same pressure range in which the resistance rapidly changes. This metallization phenomenon may be ascribed to an electronic structure transition induced by the pressure.