New Type of Quantum Criticality in the Pyrochlore Iridates

Magnetic fluctuations and electrons couple in intriguing ways in the vicinity of zero-temperature phase transitions—quantum critical points—in conducting materials. Quantum criticality is implicated in non-Fermi liquid behavior of diverse materials and in the formation of unconventional superconduct...

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Main Authors: Lucile Savary, Eun-Gook Moon, Leon Balents
Format: Article
Language:English
Published: American Physical Society 2014-11-01
Series:Physical Review X
Online Access:http://doi.org/10.1103/PhysRevX.4.041027
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spelling doaj-c3ce283bca3f424e927594519160ee252020-11-24T22:46:38ZengAmerican Physical SocietyPhysical Review X2160-33082014-11-014404102710.1103/PhysRevX.4.041027New Type of Quantum Criticality in the Pyrochlore IridatesLucile SavaryEun-Gook MoonLeon BalentsMagnetic fluctuations and electrons couple in intriguing ways in the vicinity of zero-temperature phase transitions—quantum critical points—in conducting materials. Quantum criticality is implicated in non-Fermi liquid behavior of diverse materials and in the formation of unconventional superconductors. Here, we uncover an entirely new type of quantum critical point describing the onset of antiferromagnetism in a nodal semimetal engendered by the combination of strong spin-orbit coupling and electron correlations, and which is predicted to occur in the iridium oxide pyrochlores. We formulate and solve a field theory for this quantum critical point by renormalization group techniques and show that electrons and antiferromagnetic fluctuations are strongly coupled and that both these excitations are modified in an essential way. This quantum critical point has many novel features, including strong emergent spatial anisotropy, a vital role for Coulomb interactions, and highly unconventional critical exponents. Our theory motivates and informs experiments on pyrochlore iridates and constitutes a singular realistic example of a nontrivial quantum critical point with gapless fermions in three dimensions.http://doi.org/10.1103/PhysRevX.4.041027
collection DOAJ
language English
format Article
sources DOAJ
author Lucile Savary
Eun-Gook Moon
Leon Balents
spellingShingle Lucile Savary
Eun-Gook Moon
Leon Balents
New Type of Quantum Criticality in the Pyrochlore Iridates
Physical Review X
author_facet Lucile Savary
Eun-Gook Moon
Leon Balents
author_sort Lucile Savary
title New Type of Quantum Criticality in the Pyrochlore Iridates
title_short New Type of Quantum Criticality in the Pyrochlore Iridates
title_full New Type of Quantum Criticality in the Pyrochlore Iridates
title_fullStr New Type of Quantum Criticality in the Pyrochlore Iridates
title_full_unstemmed New Type of Quantum Criticality in the Pyrochlore Iridates
title_sort new type of quantum criticality in the pyrochlore iridates
publisher American Physical Society
series Physical Review X
issn 2160-3308
publishDate 2014-11-01
description Magnetic fluctuations and electrons couple in intriguing ways in the vicinity of zero-temperature phase transitions—quantum critical points—in conducting materials. Quantum criticality is implicated in non-Fermi liquid behavior of diverse materials and in the formation of unconventional superconductors. Here, we uncover an entirely new type of quantum critical point describing the onset of antiferromagnetism in a nodal semimetal engendered by the combination of strong spin-orbit coupling and electron correlations, and which is predicted to occur in the iridium oxide pyrochlores. We formulate and solve a field theory for this quantum critical point by renormalization group techniques and show that electrons and antiferromagnetic fluctuations are strongly coupled and that both these excitations are modified in an essential way. This quantum critical point has many novel features, including strong emergent spatial anisotropy, a vital role for Coulomb interactions, and highly unconventional critical exponents. Our theory motivates and informs experiments on pyrochlore iridates and constitutes a singular realistic example of a nontrivial quantum critical point with gapless fermions in three dimensions.
url http://doi.org/10.1103/PhysRevX.4.041027
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