Anomalous electron transport in epitaxial NdNiO3 films

Ojha, Shashank Kumar and Ray, Sujay and Das, Tanmoy and Middey, S and Sarkar, Sagar and Mahadevan, Priya and Wang, Zhen and Zhu, Yimei and Liu, Xiaoran and Kareev, M and Chakhalian, J (2019) Anomalous electron transport in epitaxial NdNiO3 films. In: PHYSICAL REVIEW B, 99 (23).

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Abstract

The origin of simultaneous electronic, structural, and magnetic transitions in bulk rare-earth nickelates (RENiO3) remains puzzling with multiple conflicting reports on the nature of these entangled phase transitions. Heterostructure engineering of these materials offers unique opportunity to decouple the metal-insulator transition (MIT) from the magnetic transition. However, the evolution of underlying electronic properties across these decoupled transitions remains largely unexplored. In order to address this, we have measured Hall effect on a series of epitaxial NdNiO3 films, spanning a variety of electronic and magnetic phases. We find that the MIT results in only a partially gapped Fermi surface, whereas the full insulating phase forms below the magnetic transition. In addition, we also find a systematic reduction of the Hall coefficient R-H in the metallic phase of these films with epitaxial strain and also a surprising transition to a negative value at large compressive strain. The partially gapped, weakly insulating, paramagnetic phase is reminiscence of pseudogap behavior of high-T-c cuprates. The precursor metallic phase, which undergoes transition to the insulating phase, is a non-Fermi liquid with a temperature exponent n of resistivity of 1, whereas the exponent increases to 4/3 in the noninsulating samples. Such a nickelate phase diagram with sign reversal of R-H, a pseudogap phase, and non-Fermi-liquid behavior is intriguingly similar to high-T-c cuprates, giving important guidelines to engineer unconventional superconductivity in oxide heterostructures.

Item Type:	Journal Article
Publication:	PHYSICAL REVIEW B
Publisher:	AMER PHYSICAL SOC
Additional Information:	copyright for this article belongs to AMER PHYSICAL SOC
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	25 Sep 2019 12:03
Last Modified:	15 Oct 2019 08:55
URI:	http://eprints.iisc.ac.in/id/eprint/63223

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