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Layered Monophosphate Tungsten Bronzes [Ba(PO4)2]WmO3m−3: 2D Metals with Locked Charge‐Density‐Wave Instabilities

Phosphate tungsten and molybenum bronzes represent an outstanding class of materials displaying textbook examples of charge‐density‐wave (CDW) physics among other fundamental properties. Here we report on the existence of a novel structural branch with the general formula [Ba(PO4)2][WmO3m−3] (m=3, 4...

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Bibliographic Details
Published in:Angewandte Chemie International Edition 2023-06, Vol.62 (25), p.n/a
Main Authors: Nimoh, Hicham, Arévalo‐López, Angel Moisés, Huvé, Marielle, Minaud, Claire, Cano, Andrés, Glaum, Robert, Mentré, Olivier
Format: Article
Language:English
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Summary:Phosphate tungsten and molybenum bronzes represent an outstanding class of materials displaying textbook examples of charge‐density‐wave (CDW) physics among other fundamental properties. Here we report on the existence of a novel structural branch with the general formula [Ba(PO4)2][WmO3m−3] (m=3, 4 and 5) denominated ′layered monophosphate tungsten bronzes′ (L‐MPTB). It results from thick [Ba(PO4)2]4− spacer layers disrupting the cationic metal‐oxide 2D units and enforcing an overall trigonal structure. Their symmetries are preserved down to 1.8 K and the compounds show metallic behaviour with no clear anomaly as a function of temperature. However, their electronic structure displays the characteristic Fermi surface of previous bronzes derived from 5d W states with hidden nesting properties. By analogy with previous bronzes, such a Fermi surface should result into CDW order. Evidence of CDW order was only indirectly observed in the low‐temperature specific heat, giving an exotic context at the crossover between stable 2D metals and CDW order. In the novel MPTB series, thick insulating spacers lock a trigonal symmetry and disrupt tungsten‐oxide blocks. Contrarily to related bronzes, the 2D metallicity is steady down to 1.8 K, in absence of a charge‐density‐wave (CDW) instability through Peirls‐like W shifts. However, the 2D Fermi surfaces display the characteristics of hidden nesting, giving an exotic context at the crossover between stable 2D metals and CDW order.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.202302049