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Papers by Soumyajit Sarkar
Journal of Materials Science, 2012
Employing first-principles density functional theory based calculations we investigated the chang... more Employing first-principles density functional theory based calculations we investigated the change in electronic structure of CaCu 3 B 4 O 12 compounds as one moves from 3d (Co) to 4d (Rh) to 5d (Ir) element at B site. Our study sheds light on valences of Cu and B ions as one moves from 3d to 4d to 5d based compounds. The valence of Cu in Co and Rh compound turn out to be that of less known 3? state, while that in Ir compound turn out to be commonly known 2? state. Our first-principles study provide microscopic understanding of these different valences of Cu, in terms of changes in the mixing of Cu x 2y 2 and B-a 1g states, driven by changes in the crystal field and spin splitting. The stronger crystal field splitting for 4d and 5d elements compared to 3d at B site drive the low-spin state at Rh and Ir site as opposed to intermediate spin in case of Co.
Journal of Materials Science, 2012
Employing first-principles density functional theory based calculations we investigated the chang... more Employing first-principles density functional theory based calculations we investigated the change in electronic structure of CaCu 3 B 4 O 12 compounds as one moves from 3d (Co) to 4d (Rh) to 5d (Ir) element at B site. Our study sheds light on valences of Cu and B ions as one moves from 3d to 4d to 5d based compounds. The valence of Cu in Co and Rh compound turn out to be that of less known 3? state, while that in Ir compound turn out to be commonly known 2? state. Our first-principles study provide microscopic understanding of these different valences of Cu, in terms of changes in the mixing of Cu x 2y 2 and B-a 1g states, driven by changes in the crystal field and spin splitting. The stronger crystal field splitting for 4d and 5d elements compared to 3d at B site drive the low-spin state at Rh and Ir site as opposed to intermediate spin in case of Co.