Gaps and pseudo-gaps at the Mott quantum Critical point in the perovskite rare earth nickelates

We report on tunneling measurements that reveal for the first time the evolution of the quasi-particle state density across the bandwidth controlled Mott metal to insulator transition in the rare earth perovskite nickelates. In this, a canonical class of transition metal oxides, we study in particul...

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Bibliographic Details
Published in:arXiv.org 2014-04
Main Authors: Allen, S James, Hauser, Adam J, Mikheev, Evgeny, Zhang, Jack Y, Moreno, Nelson E, Son, Junwoo, Ouellette, Daniel G, Kally, James, Kozhanov, Alex, Balents, Leon, Stemmer, Susanne
Format: Article
Language:English
Subjects:
Antiferromagnetism
Correlation analysis
Critical point
Fermi surfaces
Insulators
Lanthanum oxides
Metal-insulator transition
Perovskites
Phase transitions
Transition metal oxides
Transition metals
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Summary:We report on tunneling measurements that reveal for the first time the evolution of the quasi-particle state density across the bandwidth controlled Mott metal to insulator transition in the rare earth perovskite nickelates. In this, a canonical class of transition metal oxides, we study in particular two materials close to the T=0 metal-insulator transition: NdNiO3 , an antiferromagnetic insulator, and LaNiO3, a correlated metal. We measure a sharp gap in NdNiO3, which has an insulating ground state, of ~ 30 meV. Remarkably, metallic LaNiO3 exhibits a pseudogap of the same order that presages the metal insulator transition. The smallness of both the gap and pseudogap suggests they arise from a common origin: proximity to a quantum critical point at or near the T=0 metal-insulator transition. It also supports theoretical models of the quantum phase transition in terms of spin and charge instabilities of an itinerant Fermi surface.
ISSN:2331-8422