Berlin 2015 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 22: Functional Materials IV: Thermoelectric and Multiferroic Materials

MM 22.5: Vortrag

Dienstag, 17. März 2015, 11:15–11:30, TC 010

Design of a Mott Multiferroic from a Non-Magnetic Polar Metal — •Gianluca Giovannetti¹, Danilo Puggioni², James Rondinelli², and Massimo Capone¹ — ¹CNR-IOM-Democritos National Simulation Centre and International School for Advanced Studies (SISSA), Via Bonomea 265, I-34136, Trieste, Italy — ²Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, USA

Metals are expected to not exhibit ferroelectricity because static internal electric fields are screened by conduction electrons. A class of materials known as "ferroelectric metals" was discussed theoretically by Anderson and Blount in 1965 [1]. Recently LiOsO₃ has been found to be a "ferroelectric metal" in the sense that it is a metal but it develops a broken-symmetry ionic structure [2]. Using a combined approach based on Density Functional Theory and Dynamical Mean Field Theory we address the driving force behind the ferroelectric instability in metallic LiOsO₃ and we show that the metallic state of LiOsO₃ is controlled by the amount of the electronic correlations of the t_2g states of Os. We unreveal how the effect of correlations of this compound can be tuned to engineer a Mott Multiferroic state in Li₂NbOsO₆ 1/1 superlattice. We find Li₂NbOsO₆ 1/1 superlattice to be a type-II multiferroic material with large ferrolectric polarization and Néel temperature close to room temperature.

[1] Anderson and Blount, Phys. Rev. Lett. 14, 217 (1965). [2] Y. Shi et Al. Nat. Mat. 12, 1024 (2013).