TY  - JOUR
AU  - Wu, H.
AU  - Burnus, T.
TI  - Spin and orbital states in La1.5 Sr0.5 CoO4 studied by electronic structure calculations
JO  - Physical review / B
VL  - 80
IS  - 8
SN  - 1098-0121
CY  - College Park, Md.
PB  - APS
M1  - PreJuSER-5600
SP  - 081105
PY  - 2009
N1  - This work was supported by the Deutsche Forschungsgemeinschaft through SFB 608.
AB  - Electronic structure of the layered perovskite La1.5Sr0.5CoO4 with a checkerboard Co2+/Co3+ charge order is studied, using the local-spin-density approximation plus Hubbard U calculations including also the spin-orbit coupling and multiplet effect. Our results show that the Co2+ ion is in a high spin state (HS, t(2g)(5)e(g)(2)) and Co3+ low spin state (LS, t(2g)(6)). Due to a small Co2+ t(2g) crystal field splitting, the spin-orbit interaction produces an orbital moment of 0.26 mu(B) and accounts for the observed easy in-plane magnetism. Moreover, we find that the Co3+ intermediate spin state (IS, t(2g)(5)e(g)(1)) has a multiplet splitting of several tenths of eV and the lowest-lying one is still higher than the LS ground state by 120 meV, and that the Co3+ HS state (t(2g)(4)e(g)(2)) is more unstable by 310 meV. Either the IS or HS Co3+ ions would give rise to a wrong magnetic order and anisotropy.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000269639300005
DO  - DOI:10.1103/PhysRevB.80.081105
UR  - https://juser.fz-juelich.de/record/5600
ER  -