Pressure-Induced Phase Transitions in Te-Se System
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The high pressure phase of Te<SUB>0. 4</SUB>Se<SUB>0. 6</SUB> can be quenched to the atmospheric pressure, and its structure was determined from single crystalline X-ray diffraction measurement. It has a monoclinic (m-) lattice with 6 atoms in a unit cell, and has a puckered layer structure containing planer zigzag chains with period 3. The zigzag chain has the bond sequence of . c-short-short-long-. c. Moreover, the superlattice structure with a unit cell size of 9 lattice constants along the baxis was found. We also detennined the structure of Tei<SUB>1-x</SUB>Se<SUB>x</SUB> mixtures in the whole concentration range (0≤x≤1) under high pressure utilizing the structural information obtained from the pressure-quenched m-Te<SUB>0. 4</SUB>Se<SUB>0. 6</SUB>. In. the Se-rich region (0. 6≤x≤1), it is observed that t- or a-Te<SUB>1-x</SUB>Se<SUB>x</SUB> is transformed into the monoclinic structure with 6 atoms in a unit cell (M-I phase). By application of pressure above 20GPa, the M-I phase is transformed into the monoclinic structure with 4 atoms in a unit cell (M-II phase). On the other hand, in the Te-rich region (0≤x≤0. 5), t-Te<SUB>1-x</SUB>Se<SUB>x</SUB> is transformed directly into the M-II phase without passing through M-I phase.
- The Review of High Pressure Science and Technology
The Review of High Pressure Science and Technology 7, 248-250, 1998
The Japan Society of High Pressure Science and Technology