http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Co₂ZrSi/ZnTe(001)계면의 자성과 반쪽금속성에 대한 제일원리 연구
김영구(Y. J. Jin),이재일(J. I. Lee) 한국자기학회 2007 韓國磁氣學會誌 Vol.17 No.4
We have investigated the half-metallicity and magnetism for the Heusler ferromagnet Co₂ZrSi interfaced with semiconductor ZnTe along the (001) plane by using the full-potential linearized augmented plane wave (FLAPW) method. We considered four types of possible interfaces: ZrSi/Zn, ZrSi/Te, Co/Zn, and Co/Te, respectively. From the calculated density of states, it was found that the halfmetallicity was lost at all the interfaces, however for the Co/Te system the value of minority spin density of states was close to zero at the Fermi level. These facts are due to the interface states, appeared in the minority spin gap in bulk Co₂ZrSi, caused by the changes of the coordination and symmetry and the hybridizations between the interface atoms. At the Co/Te interface, the magnetic moments of Co atoms are 0.68 and 0.78 μ<SUB>B</SUB> for the “bridge” and “antibridge” sites, respectively, which are much reduced with respect to that (1.15 μ<SUB>B</SUB>) of the bulk Co₂ZrSi. In the case of Co/Zn, Co atoms at the “bridge” and “antibridge” sites have magnetic moments of 1.16 and 0.93 μ<SUB>B</SUB>, respectively, which are almost same or slightly decreased compared to that of the bulk Co₂ZrSi. On the other hand, for the ZrSi/Zn and ZrSi/Te systems, the magnetic moments of Co atoms at the sub-interface layers are in the range of 1.13~1.30 μ<SUB>B</SUB>, which are almost same or slightly increased than that of the bulk Co₂ZrSi.
Ag(001) 표면 위에 놀인 Fe 선의 자성과 전자구조
김영구(Y. J. Jin),이재일(J. I. Lee) 한국자기학회 2005 韓國磁氣學會誌 Vol.15 No.4
The electronic structure and magnetism of Fe chain along the [110] direction on Ag(001) were investigated by using the all-electron full-potential linearized augmented plane wave (FLAPW) method within generalized gradient approximation (GGA). The magnetic moment of Fe atom in Fe chain is calculated to be 3.02 μ_B, which is slightly larger than that (2.99 μ_B) of the Fe[110] chain on Cu(001). The reduced coordination number for the Fe chain induced the Fe-d band narrowing and exchange-splitting enhancement, which are responsible for the large magnetic moment of the Fe chain. The calculated band width of the Fe-d band and the exchangesplitting are 1.7 eV and 3.2 eV, respectively.
Co₂TiSn(001) 표면의 자성 및 반쪽금속성에 대한 제일원리연구
김영구(Y. J. Jin),이재일(J. I. Lee) 한국자기학회 2008 韓國磁氣學會誌 Vol.18 No.4
The electronic structures, magnetism, and half-metallicity of the full-Heusler Co₂TiSn (001) surfaces have been investigated by using the all-electron full-potential linearized augmented plane wave method within the generalized gradient approximation. We have considered both of the Co atoms terminated (Co-term) and the TiSn atoms terminated (TiSn-term) surfaces. From the calculated density of states, we found that the half-metallicity was destroyed at the surface of the Co-term, while the half-metallicity was retained at the TiSn-term. For the surface of the Co-term, due to the reduced coordination number the occupied minority d-states were shifted to high energy regions and that cross the Fermi level, thus destroy the surface half-metallicity. On the other hand the surface states at the surface of the TiSn-term were located just below the Fermi level, which reduces the minority spin-gap with respect to that of the center layer. The calculated magnetic moment of the surface Co atom for the Co-term was increased by 10 % to 1.16 μB with respect to that of the inner-layers, while the magnetic moment of the subsurface Co atom in the TiSn-term has almost same value of the innerlayers (1.03 μB).