We consider the covalence characters of the 3d electron with the eg orbital freedoms and put forward a new mechanism of the orbital ordering （00） based on the direct coulomb repulsion in this article. The results sh...We consider the covalence characters of the 3d electron with the eg orbital freedoms and put forward a new mechanism of the orbital ordering （00） based on the direct coulomb repulsion in this article. The results show that the orbital-orbital interaction （OO-I） between the adjacent ions in 180-degree configuration is dominated by the superexchange energy accompanied by a weak orbital-spin coupling, and the OO-I in 90-degree configuration is monitored by the oxygen on-site coulomb repulsion. The ferro-OO is the stable ground state for the one-dimensional chain in the case of the 90-degree configuration.展开更多
We investigate the orbitM ordering quantitatively for the spinel systems RV204 （R=Mg, Zn, Cd） in the viewpoint of single-ion physics through the method of diagonalization. Through the quantitative calculation, it is...We investigate the orbitM ordering quantitatively for the spinel systems RV204 （R=Mg, Zn, Cd） in the viewpoint of single-ion physics through the method of diagonalization. Through the quantitative calculation, it is found that the spin-orbit （SO）coupling and the Jahn-Teller （JT） effect enable the orbital ordering under the conditions of negligible electron hopping among different V3＋ sites. For the systems RV204, the electron hopping is implied to be observable from the energy gap in conductivity, so the orbital ordering of RV2 04 cannot be induced by the SO coupling and JT effect at definite temperature, which is on contrary to the conclusions in [Phys. Rev. Lett. 93 （2004） 157206].展开更多
文摘We consider the covalence characters of the 3d electron with the eg orbital freedoms and put forward a new mechanism of the orbital ordering （00） based on the direct coulomb repulsion in this article. The results show that the orbital-orbital interaction （OO-I） between the adjacent ions in 180-degree configuration is dominated by the superexchange energy accompanied by a weak orbital-spin coupling, and the OO-I in 90-degree configuration is monitored by the oxygen on-site coulomb repulsion. The ferro-OO is the stable ground state for the one-dimensional chain in the case of the 90-degree configuration.
基金Supported by the State Key Project of Fundamental Research of China,under Grant No.2010CB923403
文摘We investigate the orbitM ordering quantitatively for the spinel systems RV204 （R=Mg, Zn, Cd） in the viewpoint of single-ion physics through the method of diagonalization. Through the quantitative calculation, it is found that the spin-orbit （SO）coupling and the Jahn-Teller （JT） effect enable the orbital ordering under the conditions of negligible electron hopping among different V3＋ sites. For the systems RV204, the electron hopping is implied to be observable from the energy gap in conductivity, so the orbital ordering of RV2 04 cannot be induced by the SO coupling and JT effect at definite temperature, which is on contrary to the conclusions in [Phys. Rev. Lett. 93 （2004） 157206].
