Pressure-driven collapse of the relativistic electronic ground state in a honeycomb iridate
| Autor: | Mary Upton, Yang Ding, Jennifer Sears, Jeroen van den Brink, Young-June Kim, Serge Desgreniers, Samar Layek, Yongjae Lee, Liviu Hozoi, Gregory Kh. Rozenberg, D.V. Efremov, Ning Chen, Hlynur Gretarsson, Junhyuck Im, Diego Casa, J. Patrick Clancy, Kavita Mehlawat, Yogesh Singh, Ravi Yadav |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
Strongly Correlated Electrons (cond-mat.str-el) Spins Condensed matter physics Hydrostatic pressure FOS: Physical sciences Electron lcsh:Atomic physics. Constitution and properties of matter Condensed Matter Physics 01 natural sciences lcsh:QC170-197 010305 fluids & plasmas Electronic Optical and Magnetic Materials Condensed Matter - Strongly Correlated Electrons 0103 physical sciences lcsh:TA401-492 State of matter lcsh:Materials of engineering and construction. Mechanics of materials Quantum spin liquid 010306 general physics Wave function Ground state Ambient pressure |
| Zdroj: | npj Quantum Materials, Vol 3, Iss 1, Pp 1-7 (2018) |
| ISSN: | 2397-4648 |
| DOI: | 10.1038/s41535-018-0109-0 |
| Popis: | The electronic ground state in many iridate materials is described by a complex wave-function in which spin and orbital angular momenta are entangled due to relativistic spin-orbit coupling (SOC). Such a localized electronic state carries an effective total angular momentum of $J_{eff}=1/2$. In materials with an edge-sharing octahedral crystal structure, such as the honeycomb iridates Li2IrO3 and Na2IrO3, these $J_{eff}=1/2$ moments are expected to be coupled through a special bond-dependent magnetic interaction, which is a necessary condition for the realization of a Kitaev quantum spin liquid. However, this relativistic electron picture is challenged by an alternate description, in which itinerant electrons are confined to a benzene-like hexagon, keeping the system insulating despite the delocalized nature of the electrons. In this quasi-molecular orbital (QMO) picture, the honeycomb iridates are an unlikely choice for a Kitaev spin liquid. Here we show that the honeycomb iridate Li2IrO3 is best described by a $J_{eff}=1/2$ state at ambient pressure, but crosses over into a QMO state under the application of small (~ 0.1 GPa) hydrostatic pressure. This result illustrates that the physics of iridates is extremely rich due to a delicate balance between electronic bandwidth, spin-orbit coupling, crystal field, and electron correlation. 7 pages, 5 figures, additional supplemental material included |
| Databáze: | OpenAIRE |
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