Séminaire Informel DQMP - Remarkable fluoroargentates(II) - the ultimate siblings of oxocuprates

20.01.2020 09:00 – 10:00

Remarkable fluoroargentates(II) - the ultimate siblings of oxocuprates

Wojciech Grochala

University of Warsaw, CeNT, Zwirki i Wigury 93, 02089 Warsaw Poland



Coinage group metals differ considerably from each other in terms of chemistry and physics. One particularly interesting manifestation of differences is offered by divalent state, which is enormously common and well-studied for copper, much less so for silver, while it is represented by only a handful of stoichiometries for gold. Here I will focus on compounds of divalent silver, notably fluorides. There are over a hundred of distinct stoichiometries known, most of them featuring magnetically isolated Ag(II) centers. However, some are known bearing direct Ag-F-Ag linkers (mostly in one dimension, seldom in two), which favour transmission of strong superexchange interactions. Here, I will discuss uniqueness of the crystal, electronic and magnetic structures as well as high pressure behavior of these compounds. Ultimately I will show what similarities and differences exist between them and undoped copper(II) oxides – precursors of the family of high-TC superconductors [1-9]. The prospect for achieving extremely strong antiferromagnetic superexchange in 2D [10] and 1D materials [7], as exemplified by AgF2 and AgFBF4 (or CsAgF3), respectively, will be discussed. The former compound shows profound similarities to La2CuO4, with magnetic superexchange constant reaching 70 meV (2/3 of that for the copper compound). On the other hand, AgFBF4 (or CsAgF3) feature straight 1D [AgF+] ([AgF3–]) chains with magnetic superexchange constant exceeding 300 meV (180 meV). The value of J for AgFBF4 is second to none amongst all chemical systems explored so far, and it is followed by 241 meV observed previously for Sr2CuO3 cuprate. Simultaneously, AgFBF4 exhibits magnetic anisotropy which is 2 orders of magnitude higher than that for its oxocuprate rival, rendering the former the reference 1D antiferromagnet.



[1] ANGEW CHEM INT ED ENGL 40 (15): 2742-2781 2001

[2] CHEMPHYSCHEM 4(9): 997-1001 2003

[3] NATURE MATER 5(7): 513-514 2006

[4] PHYS STAT SOL RRL 2(2): 71-73 2008

[5] ANGEW CHEM INT ED ENGL 49(9): 1683-1686 2010

[6] CHEM COMMUN 49(56): 6262-6264 2013

[7] ANGEW CHEM INT ED ENGL 56(34): 10114–10117 2017

[8] PHYS REV B 96(15): 155140 2017

[9] INORG CHEM 56(23): 14651–14661 2017

[10] PNAS 116(5): 1495–1500 2019



Biography Wojciech Grochala (b.1972) studied chemistry at the University of Warsaw (Poland) and received his Ph.D. in molecular spectroscopy under supervision of Jolanta Bukowska. After postdoctoral work in theoretical chemistry with Roald Hoffmann (Cornell, US), and in experimental inorganic and materials chemistry with Peter P. Edwards (Birmingham, UK) he returned to Poland. He obtained habilitation at the University of Warsaw in 2005, and in 2011 he was appointed Full Professor. Grochala received the Kosciuszko Foundation Fellowship (US), Royal Society of Chemistry Postdoctoral and Research Fellowships (UK), The Crescendum est Polonia Foundation Fellowship (Poland), and Świętosławski Prize 2nd degree (Polish Chem. Soc., Warsaw section). In 2014 he was granted titular professorship from the President of Poland. Since 2005 Grochala heads the Laboratory of Technology of Novel Functional Materials, with some 30 group members. He has published more than 160 papers in scientific journals and promoted 9 PhDs.

Lieu

Bâtiment: Ecole de Physique

MaNEP Room

Organisé par

Faculté des sciences
Département de physique de la matière quantique

Intervenants

Wojciech Grochala, University of Warsaw

entrée libre

Classement

Catégorie: Séminaire