Anisotropy-driven quantum criticality in an intermediate valence system.
O'Farrell, Eoin C T
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Grbić, M. S., O'Farrell, E. C. T., Matsumoto, Y., Kuga, K., Brando, M., Küchler, R., Nevidomskyy, A. H., et al. (2022). Anisotropy-driven quantum criticality in an intermediate valence system.. Nature communications, 13 (1) https://doi.org/10.1038/s41467-022-29757-9
Intermetallic compounds containing f-electron elements have been prototypical materials for investigating strong electron correlations and quantum criticality (QC). Their heavy fermion ground state evoked by the magnetic f-electrons is susceptible to the onset of quantum phases, such as magnetism or superconductivity, due to the enhanced effective mass (m<sup>*</sup>) and a corresponding decrease of the Fermi temperature. However, the presence of f-electron valence fluctuations to a non-magnetic state is regarded an anathema to QC, as it usually generates a paramagnetic Fermi-liquid state with quasiparticles of moderate m<sup>*</sup>. Such systems are typically isotropic, with a characteristic energy scale T<sub>0</sub> of the order of hundreds of kelvins that require large magnetic fields or pressures to promote a valence or magnetic instability. Here we show the discovery of a quantum critical behaviour and a Lifshitz transition under low magnetic field in an intermediate valence compound α-YbAlB<sub>4</sub>. The QC origin is attributed to the anisotropic hybridization between the conduction and localized f-electrons. These findings suggest a new route to bypass the large valence energy scale in developing the QC.
Welch Foundation (C-1818)
Deutsche Forschungsgemeinschaft (German Research Foundation) (BR 4110/1-1)
DOE | SC | Basic Energy Sciences (BES) (DE-SC0019331)
External DOI: https://doi.org/10.1038/s41467-022-29757-9
This record's URL: https://www.repository.cam.ac.uk/handle/1810/337369
Attribution 4.0 International
Licence URL: https://creativecommons.org/licenses/by/4.0/