摘要
Thermal expansion control is always an obstructive factor and challenging in high precision engineering field.Here,the negative thermal expansion of NbF_(3)and NbOF_(2)was predicted by first-principles calculation with density functional theory and the quasi-harmonic approximation(QHA).We studied the total charge density,thermal vibration,and lattice dynamic to investigate the thermal expansion mechanism.We found that the presence of O induced the relatively strong covalent bond in NbOF_(2),thus weakening the transverse vibration of F and O in NbOF_(2),compared with the case of NbF_(3).In this study,we proposed a way to tailor negative thermal expansion of metal fluorides by introducing the oxygen atoms.The present work not only predicts two NTE compounds,but also provides an insight on thermal expansion control by designing chemical bond type.
作者
Mingyue Zhang
Chunyan Wang
Yinuo Zhang
Qilong Gao
Yu Jia
张明月;王春艳;张一诺;高其龙;贾瑜(International Laboratory for Quantum Functional Materials of Henan,and School of Physics and Microelectronics,Zhengzhou University,Zhengzhou 450052,China;Key Laboratory of Special Functional Materials of Ministry of Education,and School of Materials Science and Engineering,Henan University,Henan 475001,China)
基金
the National Natural Science Foundation of China(Grant Nos.11774078 and 21905252)
China Postdoctoral Science Foundation(Grant No.2019M652558)
Innovation Scientists and Technicians Troop Construction Projects of Henan Province,China(Grant No.10094100510025).
