TY - JOUR
T1 - First-principles study of crystal structural stability and electronic and magnetic properties in LaMn7O12
AU - Liu, X. J.
AU - Lv, S. H.
AU - Pan, E.
AU - Meng, J.
AU - Albrecht, J. D.
PY - 2010
Y1 - 2010
N2 - The crystal structure, electronic and magnetic properties of LaMn 7O12 ((LaMn33+)AMn 43+O12) are investigated by GGA (LSDA) and GGA + U (LSDA + U) (0.0 ≤ U ≤ 5.0eV) methods. Based on two experimentally refined structures (distinguished by the distortion parameter Δ, namely SI (Δ = 8.5 × 10-5) and SII (Δ = 25.0 × 10-4)), GGA and GGA + U with U < 3.0eV calculations indicate that SI with a small distortion is the lowest-energy crystal structure while GGA + U with 3.0 ≤ U ≤ 5.0eV calculations show that SII with a larger distortion is the ground-state crystal structure. Within the LSDA method, SII is always the ground-state structure no matter if U is considered or not. There are two independent magnetic sublattices: Mn3+ within the A site and Mn 3+ within the B site. First, it is predicted that A-site Mn 3+ ions are preferably AFM-coupled in G-type (antiferromagnetically coupled in three directions). Based on this result, four magnetic configurations (FM-A↑↑B↑↑, AFM1-A↑↑B↓↓, AFM2-A↑↓B↑↑ and AFM3-A↑↓B↑↓) are designed, and their total energies are calculated. Our results demonstrate that AFM2 and AFM3 are the lowest magnetic state, respectively, for SI and SII. Correspondingly, LaMn7O12 is metallic with no orbital ordering at AFM2 for SI while it is an insulator with orbital ordering at AFM3 for SII. Thus, modulation of the distortion parameter Δ, e.g. by chemical doping, could be employed as a new avenue to induce a magnetic phase transition and the corresponding metal-to-insulator transition in LaMn7O12.
AB - The crystal structure, electronic and magnetic properties of LaMn 7O12 ((LaMn33+)AMn 43+O12) are investigated by GGA (LSDA) and GGA + U (LSDA + U) (0.0 ≤ U ≤ 5.0eV) methods. Based on two experimentally refined structures (distinguished by the distortion parameter Δ, namely SI (Δ = 8.5 × 10-5) and SII (Δ = 25.0 × 10-4)), GGA and GGA + U with U < 3.0eV calculations indicate that SI with a small distortion is the lowest-energy crystal structure while GGA + U with 3.0 ≤ U ≤ 5.0eV calculations show that SII with a larger distortion is the ground-state crystal structure. Within the LSDA method, SII is always the ground-state structure no matter if U is considered or not. There are two independent magnetic sublattices: Mn3+ within the A site and Mn 3+ within the B site. First, it is predicted that A-site Mn 3+ ions are preferably AFM-coupled in G-type (antiferromagnetically coupled in three directions). Based on this result, four magnetic configurations (FM-A↑↑B↑↑, AFM1-A↑↑B↓↓, AFM2-A↑↓B↑↑ and AFM3-A↑↓B↑↓) are designed, and their total energies are calculated. Our results demonstrate that AFM2 and AFM3 are the lowest magnetic state, respectively, for SI and SII. Correspondingly, LaMn7O12 is metallic with no orbital ordering at AFM2 for SI while it is an insulator with orbital ordering at AFM3 for SII. Thus, modulation of the distortion parameter Δ, e.g. by chemical doping, could be employed as a new avenue to induce a magnetic phase transition and the corresponding metal-to-insulator transition in LaMn7O12.
UR - http://www.scopus.com/inward/record.url?scp=77953118060&partnerID=8YFLogxK
U2 - 10.1088/0953-8984/22/24/246001
DO - 10.1088/0953-8984/22/24/246001
M3 - Article
AN - SCOPUS:77953118060
SN - 0953-8984
VL - 22
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
IS - 24
M1 - 246001
ER -