Charge disproportionate antiferromagnetism at the verge of the insulator-metal transition in doped LaFeO3

Jana, S and Panda, SK and Phuyal, D and Pal, B and Mukherjee, S and Dutta, A and Kumar, P Anil and Hedlund, D and Schott, J and Thunstrom, P and Kvashnin, Y and Rensmo, H and Kamalakar, M Venkata and Segre, Carlo U and Svedlindh, P and Gunnarsson, K and Biermann, S and Eriksson, O and Karis, O and Sarma, DD (2019) Charge disproportionate antiferromagnetism at the verge of the insulator-metal transition in doped LaFeO3. In: PHYSICAL REVIEW B, 99 (7).

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Abstract

We explore the effects of electron doping in lanthanum ferrite, LaFeO3 by doping Mo at the Fe sites. Based on magnetic, transport, scanning tunneling spectroscopy, and x-ray photoelectron spectroscopy measurements, we find that the large gap, charge-transfer, antiferromagnetic (AFM) insulator LaFeO3 becomes a small gap AFM band insulator at low Mo doping. With increasing doping concentration, Mo states, which appear around the Fermi level, is broadened and become gapless at a critical doping of 20%. Using a combination of calculations based on density functional theory plus Hubbard U (DFT+U) and x-ray absorption spectroscopy measurements, we find that the system shows charge disproportionation (CD) in Fe ions at 25% Mo doping, where two distinct Fe sites, having Fe2+ and Fe3+ nominal charge states appear. A local breathing-type lattice distortion induces the charge disproportionation at the Fe site without destroying the antiferromagnetic order. Our combined experimental and theoretical investigations establish that the Fe states form a CD antiferromagnet at 25% Mo doping, which remains insulating, while the appearance of Mo states around the Fermi level is showing an indication towards the insulator-metal transition.

Item Type:	Journal Article
Publication:	PHYSICAL REVIEW B
Publisher:	AMER PHYSICAL SOC
Additional Information:	Copyright of this article belongs to AMER PHYSICAL SOC
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	25 Feb 2019 04:54
Last Modified:	25 Feb 2019 04:54
URI:	http://eprints.iisc.ac.in/id/eprint/61817

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