Density functional theory calculations are performed to study the structural, electronic and magnetic properties of hexagonal NiAs type and cubic zinc blende type MnSb structure and interface of zinc blende MnSb with ...Density functional theory calculations are performed to study the structural, electronic and magnetic properties of hexagonal NiAs type and cubic zinc blende type MnSb structure and interface of zinc blende MnSb with GaSb（001）. We used generalized gradiant approximation to calculate the exchange-correlation term in bulk and interface determination. The zinc blende structure of MnSb is found to be ferromagnetic half-metal with a total moment of 4 μB per formula unit. Results show that the half-metallicity character is preserved at MnSb/GaSb（001） interface. The magnetic moment of Mn atom in interface is reduced and the magnetic moment of the interface Sb atom is equal to the average of the corresponding bulk values in two sides of the interface. The band alignment properties are also computed and a rather large minority valance band offset of about 1.25 eV is obtained in this heterojunction.展开更多
BP( Back Propagation) neural network and PSO( Particle Swarm Optimization) are two main heuristic optimization methods,and are usually used as nonlinear inversion methods in geophysics. The authors applied BP neural n...BP( Back Propagation) neural network and PSO( Particle Swarm Optimization) are two main heuristic optimization methods,and are usually used as nonlinear inversion methods in geophysics. The authors applied BP neural network and BP neural network optimized with PSO into the inversion of 3D density interface respectively,and a comparison was drawn to demonstrate the inversion results. To start with,a synthetic density interface model was created and we used the proceeding inversion methods to test their effectiveness. And then two methods were applied into the inversion of the depth of Moho interface. According to the results,it is clear to find that the application effect of PSO-BP is better than that of BP network. The BP network structures used in both synthetic and field data are consistent in order to obtain preferable inversion results. The applications in synthetic and field tests demonstrate that PSO-BP is a fast and effective method in the inversion of 3D density interface and the optimization effect is evident compared with BP neural network merely,and thus,this method has practical value.展开更多
文摘Density functional theory calculations are performed to study the structural, electronic and magnetic properties of hexagonal NiAs type and cubic zinc blende type MnSb structure and interface of zinc blende MnSb with GaSb（001）. We used generalized gradiant approximation to calculate the exchange-correlation term in bulk and interface determination. The zinc blende structure of MnSb is found to be ferromagnetic half-metal with a total moment of 4 μB per formula unit. Results show that the half-metallicity character is preserved at MnSb/GaSb（001） interface. The magnetic moment of Mn atom in interface is reduced and the magnetic moment of the interface Sb atom is equal to the average of the corresponding bulk values in two sides of the interface. The band alignment properties are also computed and a rather large minority valance band offset of about 1.25 eV is obtained in this heterojunction.
基金Supported by National High-tech Research&Development Program of China(863 Project)(No.2014AA06A613)
文摘BP( Back Propagation) neural network and PSO( Particle Swarm Optimization) are two main heuristic optimization methods,and are usually used as nonlinear inversion methods in geophysics. The authors applied BP neural network and BP neural network optimized with PSO into the inversion of 3D density interface respectively,and a comparison was drawn to demonstrate the inversion results. To start with,a synthetic density interface model was created and we used the proceeding inversion methods to test their effectiveness. And then two methods were applied into the inversion of the depth of Moho interface. According to the results,it is clear to find that the application effect of PSO-BP is better than that of BP network. The BP network structures used in both synthetic and field data are consistent in order to obtain preferable inversion results. The applications in synthetic and field tests demonstrate that PSO-BP is a fast and effective method in the inversion of 3D density interface and the optimization effect is evident compared with BP neural network merely,and thus,this method has practical value.
