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Origin of the Charge Gap in LaMnPO

Published

Author(s)

D. E. McNally, J. W. Simonson, K. W. Post, Z. P. Yin, M. Pezzoli, G. J. Smith, V. Leyva, C. Marques, L. DeBeer-Schmitt, A. I. Kolesnikov, Yang Zhao, Jeffrey W. Lynn, D. N. Basov, G. Kotliar, M. C. Aronson

Abstract

We present inelastic neutron scattering and magnetization measurements of the antiferromagnetic insulator LaMnPO that are well described by a Heisenberg spin model. These measurements are consistent with the presence of two-dimensional magnetic correlations up to a temperature Τmax approximately equal} 700K >> ΤN = 375 K, the Neel temperature. Optical transmission measurements show the Τ=300 K direct charge gap Δ} = 1eV has decreased by only 10% at Τmax. Density functional theory and dynamical mean field theory calculations reproduce a direct charge gap in paramagnetic LaMnPO only when a strong Hund's coupling JH = 0.9 eV is included, as well as onsite Hubbard U = 8 eV. These results show the direct charge gap in LaMnPO is rather insensitive to antiferromagnetic exchange coupling and instead is a result of the local physics governed by U and JH.
Citation
Physical Review B
Volume
90
Issue
5

Keywords

Antiferromagnet (375 K), Insulator, Spin dynamics, Inelastic Neutron Scattering, Density functional theory, Hund's coupling, Hubbard U

Citation

McNally, D. , Simonson, J. , Post, K. , Yin, Z. , Pezzoli, M. , Smith, G. , Leyva, V. , Marques, C. , DeBeer-Schmitt, L. , Kolesnikov, A. , Zhao, Y. , Lynn, J. , Basov, D. , Kotliar, G. and Aronson, M. (2014), Origin of the Charge Gap in LaMnPO, Physical Review B, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=915716 (Accessed May 20, 2024)

Issues

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Created November 17, 2014, Updated October 12, 2021