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Langmann J, Eickerling G, Scherer W. X-ray diffraction – a suitable probe for superconductivity? Acta Cryst Sect A 2022. [DOI: 10.1107/s2053273322095602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
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Geirhos K, Langmann J, Prodan L, Tsirlin AA, Missiul A, Eickerling G, Jesche A, Tsurkan V, Lunkenheimer P, Scherer W, Kézsmárki I. Cooperative Cluster Jahn-Teller Effect as a Possible Route to Antiferroelectricity. Phys Rev Lett 2021; 126:187601. [PMID: 34018769 DOI: 10.1103/physrevlett.126.187601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 03/02/2021] [Accepted: 04/08/2021] [Indexed: 06/12/2023]
Abstract
We report the observation of an antipolar phase in cubic GaNb_{4}S_{8} driven by an unconventional microscopic mechanism, the cooperative Jahn-Teller effect of Nb_{4}S_{4} molecular clusters. The assignment of the antipolar nature is based on sudden changes in the crystal structure and a strong drop of the dielectric constant at T_{JT}=31 K, also indicating the first-order nature of the transition. In addition, we found that local symmetry lowering precedes long-range orbital ordering, implying the presence of a dynamic Jahn-Teller effect in the cubic phase above T_{JT}. Based on the variety of structural polymorphs reported in lacunar spinels, also including ferroelectric phases, we argue that GaNb_{4}S_{8} may be transformable to a ferroelectric state, which would further classify the observed antipolar phase as antiferroelectric.
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Affiliation(s)
- K Geirhos
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - J Langmann
- CPM, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany
| | - L Prodan
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
- Institute of Applied Physics, MD 2028, Chisinau, Republic of Moldova
| | - A A Tsirlin
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - A Missiul
- CELLS-ALBA Synchrotron, Cerdanyola del Valles, E-08290 Barcelona, Spain
| | - G Eickerling
- CPM, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany
| | - A Jesche
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - V Tsurkan
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
- Institute of Applied Physics, MD 2028, Chisinau, Republic of Moldova
| | - P Lunkenheimer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - W Scherer
- CPM, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany
| | - I Kézsmárki
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
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