arXiv subjects

Imseok Yang

Publications and source records attributed to Imseok Yang.

3 recordsLinked to original sources

arXiv2001

Importance of Correlation Effects on Magnetic Anisotropy in Fe and Ni

We calculate magnetic anisotropy energy of Fe and Ni by taking into account the effects of strong electronic correlations, spin-orbit coupling, and non-collinearity of intra--atomic magnetization. The LDA+U method is used and its equivalence to dynamical mean--field theory in the static limit is emphasized. Both experimental magnitude of MAE and direction of magnetization are predicted correctly near U=1.9 eV, J=1.2 eV for Ni and U=1.2 eV, J=0.8 eV for Fe. Correlations modify the one--electron spectra which are now in better agreement with experiments.

cond-mat.str-el↗

arXiv2000

Importance of Correlation Effects on Magnetic Anisotropy in Fe and Ni

We calculate magnetic anisotropy energy of Fe and Ni by taking into account the effects of strong electronic correlations, spin-orbit coupling, and non-collinearity of intra-atomic magnetization. The LDA+U method is used and its equivalence to dynamical mean-field theory in the static limit is emphasized. Both experimental magnitude of MAE and direction of magnetization are predicted correctly near U=4 eV for Ni and U=3.5 eV for Fe. Correlations modify one-electron spectra which are now in better agreement with experiments.

cond-mat.str-el↗

arXiv2000

Impact of magnetic frustration on the Mott transition within a slave-boson mean-field theory

We investigate the paramagnetic-metal-to-antiferromagnetic-metal and antiferromagnetic-metal-to- antiferromagnetic-insulator transitions using a slave-boson mean-field theory. To this effect, we discuss the ground state of the half-filled Hubbard model as a function of t'/t and correlation strength U, where t and t' are the hopping amplitudes between nearest and next-nearest neighbors, respectively. The metal-insulator transition at a critical U_{MIT} is of second order for small levels of magnetic frustration, t'/t<0.06, and of first order for large ones, t'/t>0.06. The insulator is always antiferromagnetically ordered, while the metal exhibits a second-order transition from a paramagnetic to an antiferromagnetic state up to t'/t=0.14, as U is increased. We also contrast these findings with what we obtain in Hartree-Fock approximation.

cond-mat.str-el↗