Identification of the pressure-induced phase transition of ZnSe with the positron annihilation method

• Published in: Chinese physics B 2011-10, Vol.20 (10), p.452-456, Article 108105
• Main Authors: Liu, Jian-Dang (建党 刘), Cheng, Bin (斌成), Zhang, Jie (杰张), Zhang, Li-Juan (丽娟 张), Weng, Hui-Min (惠民 翁), Ye, Bang-Jiao (邦角 叶)
• Format: Article
• Language: English
• Subjects: Approximation; Atomic structure; Mathematical analysis; NaCl胁迫; Phase transformations; Positron annihilation; Positrons; Transition pressure; Zinc selenides; ZnSe; 压力诱导相变; 寿命计算; 正电子湮没; 赝势平面波方法; 鉴定; 静水压力
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/20/10/108105

This paper studies the pressure-induced phase transition between zincblende （B3） and NaC1 （B1） structure ZnSe by using the hydrostatic pressure first-principles pseudopotential plane wave method. The energy-volume and enthalpy- pressure curves are employed to estimate the transition pressure. It is found that ZnSe undergoes a first-order phase transition from the B3 structure to the B1 structure at approximately 15 GPa derived from the energy-volume relation and 14 GPa based on deduction from enthalpy pressure data. The pressure-related positron bulk lifetimes of the two ZnSe structures are calculated with the atomic superposition approximation method. In comparison with the 13.4% reduction in volume of ZnSe at the transition pressure, the positron bulk lifetime decreases more significantly and the relative value declines up to 22.3%. The results show that positron annihilation is an effective technique to identify and characterize the first-order phase transition and can give valuable information about changes in micro-scale, such as volume shrinkage and compressibility.