The spin-dependent electronic transport properties of a zigzag zinc oxide(ZnO) nanoribbon are studied by using density functional theory with non-equilibrium Green's functions. We calculate the spin-polarized band...The spin-dependent electronic transport properties of a zigzag zinc oxide(ZnO) nanoribbon are studied by using density functional theory with non-equilibrium Green's functions. We calculate the spin-polarized band structure, projected density of states, Bloch states, and transmission spectrum of the ZnO nanoribbon. It is determined that all Bloch states are located at the edge of the ZnO nanoribbon. The spin-up transmission eigenchannels are contributed from Zn 4s orbital,whereas the spin-down transmission eigenchannels are contributed from Zn 4s and O 2p orbitals. By analyzing the current-voltage curves for the opposite spins of the ZnO nanoribbon device, negative differential resistance(NDR) and spin filter effect are observed. Moreover, by constructing the ZnO nanoribbon modified by the Zn-edge defect, the spin-up current is severely suppressed because of the destruction of the spin-up transmission eigenchannels. However, the spin-down current is preserved, thus resulting in the perfect spin filter effect. Our results indicate that the ZnO nanoribbon modulated by the edge defect is a practical design for a spin filter.展开更多
The scattering matrices of e+N^(+)with J^(π)=1.5^(+)in discrete energy regions are calculated using the eigenchannel R-matrix method.We obtain good parameters of multichannel quantum defect theory(MQDT)that vary smoo...The scattering matrices of e+N^(+)with J^(π)=1.5^(+)in discrete energy regions are calculated using the eigenchannel R-matrix method.We obtain good parameters of multichannel quantum defect theory(MQDT)that vary smoothly as the function of the energy resulting from the analytical continuation property of the scattering matrices.By employing the MQDT,all discrete energy levels for N could be calculated accurately without missing anyone.The MQDT parameters(i.e.,scattering matrices)can be calibrated with the available precise spectroscopy values.In this work,the optical oscillator strengths for the transition between the ground state and Rydberg series are obtained,which provide rich data for the diagnostic analysis of plasma.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61664008 and 11604286)the Scientific Technological Innovation Team of Yan’an City,China(Grant No.2017CXTD-01)
文摘The spin-dependent electronic transport properties of a zigzag zinc oxide(ZnO) nanoribbon are studied by using density functional theory with non-equilibrium Green's functions. We calculate the spin-polarized band structure, projected density of states, Bloch states, and transmission spectrum of the ZnO nanoribbon. It is determined that all Bloch states are located at the edge of the ZnO nanoribbon. The spin-up transmission eigenchannels are contributed from Zn 4s orbital,whereas the spin-down transmission eigenchannels are contributed from Zn 4s and O 2p orbitals. By analyzing the current-voltage curves for the opposite spins of the ZnO nanoribbon device, negative differential resistance(NDR) and spin filter effect are observed. Moreover, by constructing the ZnO nanoribbon modified by the Zn-edge defect, the spin-up current is severely suppressed because of the destruction of the spin-up transmission eigenchannels. However, the spin-down current is preserved, thus resulting in the perfect spin filter effect. Our results indicate that the ZnO nanoribbon modulated by the edge defect is a practical design for a spin filter.
基金Project supported by the Science Challenge Project(Grant No.TZ2016005)the National Key Research and Development Program of China(Grant Nos.2017YFA0403200 and 2017YFA0402300)the CAEP Foundation(Grant No.CX2019022)。
文摘The scattering matrices of e+N^(+)with J^(π)=1.5^(+)in discrete energy regions are calculated using the eigenchannel R-matrix method.We obtain good parameters of multichannel quantum defect theory(MQDT)that vary smoothly as the function of the energy resulting from the analytical continuation property of the scattering matrices.By employing the MQDT,all discrete energy levels for N could be calculated accurately without missing anyone.The MQDT parameters(i.e.,scattering matrices)can be calibrated with the available precise spectroscopy values.In this work,the optical oscillator strengths for the transition between the ground state and Rydberg series are obtained,which provide rich data for the diagnostic analysis of plasma.
