With modified analytical embedded-atom method and molecular dynamics simulation, this paper simulates the strain energy and the equilibrium core structure of a（100） edge dislocation in BCC metal iron on atomistic sc...With modified analytical embedded-atom method and molecular dynamics simulation, this paper simulates the strain energy and the equilibrium core structure of a（100） edge dislocation in BCC metal iron on atomistic scale. In addition, the trapping effect of dislocation on vacancy is investigated as well. The results show that the equilibrium dislocation core is quite narrow and has a C2v symmetry structure. Calculated strain energy Es of the dislocation is a linear function of ln（R/2b） while R ≥ 5.16 A（1A = 0.1 nm）, in excellent agreement with the elasticity theory prediction. Determined core radius and energy are 5.16 A and 0.62 eV/A, respectively. The closer the vacancy to the dislocation line is, the lower the vacancy formation energy is, this fact implies that the dislocation has a trend to trap the vacancy, especially for a separation distance of the vacancy from dislocation line being less than two lattice constants.展开更多
All dielectrics exhibit electrostriction,i.e.,display a quadratic strain response to an electric field compared to the linear strain dependence of piezoelectrics.As such,there is significant interest in discovering ne...All dielectrics exhibit electrostriction,i.e.,display a quadratic strain response to an electric field compared to the linear strain dependence of piezoelectrics.As such,there is significant interest in discovering new electrostrictors with enhanced electrostrictive coefficients,especially as electrostrictors can exhibit effective piezoelectricity when a bias electric field is applied.We present the results of a study combining data mining and first-principles computations that indicate that there exists a group of iodides,bromides,and chlorides that have electrostrictive coefficients exceeding 10 m^(4)C^(–2)which are substantially higher than typical oxide electrostrictive ceramics and polymers.The corresponding effective piezoelectric voltage coefficients are three orders of magnitude larger than lead zirconate titanate.展开更多
基金supported by the State Key Development Program for Basic Research of China (Grant No. 2004CB619302)the National Natural Science Foundation of China (Grant No. 51071098)
文摘With modified analytical embedded-atom method and molecular dynamics simulation, this paper simulates the strain energy and the equilibrium core structure of a（100） edge dislocation in BCC metal iron on atomistic scale. In addition, the trapping effect of dislocation on vacancy is investigated as well. The results show that the equilibrium dislocation core is quite narrow and has a C2v symmetry structure. Calculated strain energy Es of the dislocation is a linear function of ln（R/2b） while R ≥ 5.16 A（1A = 0.1 nm）, in excellent agreement with the elasticity theory prediction. Determined core radius and energy are 5.16 A and 0.62 eV/A, respectively. The closer the vacancy to the dislocation line is, the lower the vacancy formation energy is, this fact implies that the dislocation has a trend to trap the vacancy, especially for a separation distance of the vacancy from dislocation line being less than two lattice constants.
基金Authors A.G.,S.K.N.,and S.P.A.thank the Air Force Research Laboratory,Materials and Manufacturing Directorate(AFRL/RXMS)for support via Contract No.FA8650-18-C-5700J.Y.and P.E.J.have been supported by the ANR-19-ASTR-0024-01 and ANR-20-CE08-0012-1 grants.
文摘All dielectrics exhibit electrostriction,i.e.,display a quadratic strain response to an electric field compared to the linear strain dependence of piezoelectrics.As such,there is significant interest in discovering new electrostrictors with enhanced electrostrictive coefficients,especially as electrostrictors can exhibit effective piezoelectricity when a bias electric field is applied.We present the results of a study combining data mining and first-principles computations that indicate that there exists a group of iodides,bromides,and chlorides that have electrostrictive coefficients exceeding 10 m^(4)C^(–2)which are substantially higher than typical oxide electrostrictive ceramics and polymers.The corresponding effective piezoelectric voltage coefficients are three orders of magnitude larger than lead zirconate titanate.
