Shenton, JK;
Bowler, DR;
Cheah, WL;
(2017)
Effects of the Hubbard U on density functional-based predictions of BiFeO3 properties.
Journal of Physics: Condensed Matter
, 29
(44)
, Article 445501. 10.1088/1361-648X/aa8935.
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Abstract
First principles studies of multiferroic materials, such as bismuth ferrite (BFO), require methods that extend beyond standard density functional theory (DFT). The DFT + U method is one such extension that is widely used in the study of BFO. We present a systematic study of the effects of the U parameter on the structural, ferroelectric and electronic properties of BFO. We find that the structural and ferroelectric properties change negligibly in the range of U typically considered for BFO (3–5 eV). In contrast, the electronic structure varies significantly with U. In particular, we see large changes to the character and curvature of the valence band maximum and conduction band minimum, in addition to the expected increase in band gap, as U increases. Most significantly, we find that the $t_{2g}$ /$e_{g}$ ordering at the conduction band minimum inverts for U values larger than 4 eV. We therefore recommend a U value of at most 4 eV to be applied to the Fe d orbitals in BFO. More generally, this study emphasises the need for systematic investigations of the effects of the U parameter not merely on band gaps but on the electronic structure as a whole, especially for strongly correlated materials.
Type: | Article |
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Title: | Effects of the Hubbard U on density functional-based predictions of BiFeO3 properties |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1088/1361-648X/aa8935 |
Publisher version: | http://dx.doi.org/10.1088/1361-648X/aa8935 |
Language: | English |
Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
URI: | https://discovery.ucl.ac.uk/id/eprint/1572277 |
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