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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Quantum criticality in a layered iridate

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Samanta, Kousik [1] ; Souza, Jean C. [1] ; Rigitano, Danilo [1] ; Morales, Adimir I. [1] ; Pagliuso, Pascoal G. [1] ; Granado, Eduardo [1]
Total Authors: 6
[1] Univ Campinas UNICAMP, Gleb Wataghin Inst Phys, Campinas, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: COMMUNICATIONS PHYSICS; v. 4, n. 1 MAY 10 2021.
Web of Science Citations: 0

Iridates provide a fertile ground to investigate correlated electrons in the presence of strong spin-orbit coupling. Bringing these systems to the proximity of a metal-insulator quantum phase transition is a challenge that must be met to access quantum critical fluctuations with charge and spin-orbital degrees of freedom. Here, electrical transport and Raman scattering measurements provide evidence that a metal-insulator quantum critical point is effectively reached in 5% Co-doped Sr2IrO4 with high structural quality. The dc-electrical conductivity shows a linear temperature dependence that is successfully captured by a model involving a Co acceptor level at the Fermi energy that becomes gradually populated at finite temperatures, creating thermally-activated holes in the J(eff)=1/2 lower Hubbard band. The so-formed quantum critical fluctuations are exceptionally heavy and the resulting electronic continuum couples with an optical phonon at all temperatures. The magnetic order and pseudospin-phonon coupling are preserved under the Co doping. This work brings quantum phase transitions, iridates and heavy-fermion physics to the same arena. Due to a combination of strong spin orbit coupling and electron correlations iridates such as Sr2IrO4 exhibit a range of exotic quantum states that can be tuned via their electronic and magnetic properties. Here, the authors investigate the resistive and Raman scattering properties of Co-doped Sr2IrO4 and provide evidence for quantum critical fluctuations in the system. (AU)

FAPESP's process: 18/11364-7 - Magnetic properties of complex systems with non-trivial topology
Grantee:Jean Carlo Souza
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 18/18653-4 - Search for emergent electronic states in the two-dimensional Iridates (Sr1-xAx)2IrO4 (A=Ca, BA)
Grantee:Adimir Italo Vilca Morales
Support type: Scholarships in Brazil - Master
FAPESP's process: 17/10581-1 - Emergent phenomena in reduced dimension systems
Grantee:Pascoal Jose Giglio Pagliuso
Support type: Research Projects - Thematic Grants
FAPESP's process: 16/00756-6 - Synthesis and Fundamental Investigation of Novel Correlated Electron Systems with Strong Spin-orbit Coupling
Grantee:Kousik Samanta
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 18/20142-8 - Vibrational dynamics, spin waves and orbital excitations in transition-metal oxides
Grantee:Eduardo Granado Monteiro da Silva
Support type: Regular Research Grants