Seminar of Physics at Wrocław University of Technology
Platforma Zoom
Odkrycie krytycznych fluktuacji w przejściu Verweya w magnetycie
dr hab. Przemysław Piekarz, prof. IFJ PAN
Instytut Fizyki Jądrowej PAN, Kraków
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Streszczenie:
The Verwey transition in magnetite (Fe3O4), in which the electrical conductivity changes discontinuously by two orders of magnitude, is one of the most intriguing phenomena in condensed matter physics. The exceptional character of this phase transition results from a cooperative mechanism involving charge, orbital, spin, and lattice degrees of freedom. At the Verwey temperature Tv=124 K, magnetite exhibits the structural phase transformation from the cubic to monoclinic phase with the charge-orbital order composed of three-site polarons, called trimerons. Recently, we discovered the soft fluctuations of the trimeron order showing critical behavior close to the Verwey transition [E. Baldini et al., Nature Physics 16, 541 (2020)]. These fluctuations were described within a polaron tunneling model, which involves the coupling between trimerons and phonons.
