The effects of hydrostatic pressure of SrWeO3 are investigated by means of generalized gradient approximation （GGA） plus on-site Coulomb interaction corrections （GGA＋U） method within the framework of density func...The effects of hydrostatic pressure of SrWeO3 are investigated by means of generalized gradient approximation （GGA） plus on-site Coulomb interaction corrections （GGA＋U） method within the framework of density functional theory （DFT）. Magnetic phase diagrams and structural parameters of SrTcO3 as a function of pressure are predicted. The magnetic ground state of SrTcO3 is found to keep in a G-type antiferromagnetic （G-AFM） structure under the pressure varying from 0 to 100 GPa. With the increase of the pressure, magnetic exchange energy increases, indicating a higher magnetic ordering temperature for SrTcO3 under a larger pressure. Besides the volume of the unit cell, lattice constants, and the bond length, the angles between typical Tc-O-Tc and Sr-O-Sr also decrease with the pressure, leading to strong structural distortions. Very obvious displace- ments of Sr and O atoms are observed under the pressure. Our work provides necessary understanding on electronic structures of SrTcO3 under high pressures.展开更多
The binding energy and Stark effect energy shifts of a shallow donor impurity state in a strained GaN/AlxGa1-xN spherical finite-potential quantum dot (QD) are calculated using a variational method based on the effect...The binding energy and Stark effect energy shifts of a shallow donor impurity state in a strained GaN/AlxGa1-xN spherical finite-potential quantum dot (QD) are calculated using a variational method based on the effective mass approximation. The binding energy is computed as a function of dot size and hydrostatic pressure. The numerical results show that the binding energy of the impurity state increases, attains a maximum value, and then decreases as the QD radius increases for any electric field. Moreover, the binding energy increases with the pressure for any size of dot. The Stark shift of the impurity energy for large dot size is much larger than that for the small dot size, and it is enhanced by the increase of electric field. We compare the binding energy of impurity state with and without strain effects, and the results show that the strain effects enhance the impurity binding energy considerably, especially for the small QD size. We also take the dielectric mismatch into account in our work.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 10904104 and 11164026)the High Performance Computing Center of Suzhou University of Science and Technology(SUST)
文摘The effects of hydrostatic pressure of SrWeO3 are investigated by means of generalized gradient approximation （GGA） plus on-site Coulomb interaction corrections （GGA＋U） method within the framework of density functional theory （DFT）. Magnetic phase diagrams and structural parameters of SrTcO3 as a function of pressure are predicted. The magnetic ground state of SrTcO3 is found to keep in a G-type antiferromagnetic （G-AFM） structure under the pressure varying from 0 to 100 GPa. With the increase of the pressure, magnetic exchange energy increases, indicating a higher magnetic ordering temperature for SrTcO3 under a larger pressure. Besides the volume of the unit cell, lattice constants, and the bond length, the angles between typical Tc-O-Tc and Sr-O-Sr also decrease with the pressure, leading to strong structural distortions. Very obvious displace- ments of Sr and O atoms are observed under the pressure. Our work provides necessary understanding on electronic structures of SrTcO3 under high pressures.
基金supported by the National Natural Science Foundation of China (No.10964006)the Research Funds for the Science and Technology Innovation Team of Inner Mongolia Agricultural University (No. NDPYTD2010-7)
文摘The binding energy and Stark effect energy shifts of a shallow donor impurity state in a strained GaN/AlxGa1-xN spherical finite-potential quantum dot (QD) are calculated using a variational method based on the effective mass approximation. The binding energy is computed as a function of dot size and hydrostatic pressure. The numerical results show that the binding energy of the impurity state increases, attains a maximum value, and then decreases as the QD radius increases for any electric field. Moreover, the binding energy increases with the pressure for any size of dot. The Stark shift of the impurity energy for large dot size is much larger than that for the small dot size, and it is enhanced by the increase of electric field. We compare the binding energy of impurity state with and without strain effects, and the results show that the strain effects enhance the impurity binding energy considerably, especially for the small QD size. We also take the dielectric mismatch into account in our work.
