Berlin 2018 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 86: Ferroics and Multiferroics (joint session KFM/TT/MA)
TT 86.6: Talk
Thursday, March 15, 2018, 11:10–11:30, EMH 225
Screening in metallized ferroelectrics — •Hongjian Zhao1, Alessio Filippetti2,3, Carlos Escorihuela-Sayalero1, Pietro Delugas4, Enric Canadell5, Laurent Bellaiche6, Vincenzo Fiorentini2,3, and Jorge Íñiguez1 — 1Materials Research and Technology Department, Luxembourg Institute of Science and Technology, Luxembourg — 2Dipartimento di Fisica, Università di Cagliari, Cittadella Universitaria, Italy — 3CNR-IOM SLACS, Cittadella Universitaria, Italy — 4Scuola Internazionale Superiore di Studi Avanzati, Italy — 5Institut de Ciència de Materials de Barcelona, Spain — 6Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, USA
Ferroelectric materials are characterized by spontaneous polar distortions. The behavior of such distortions in the presence of free charge is the key to the physics of metallized ferroelectrics in particular, and of structurally-polar metals more generally. Using first-principles simulations, here we show that polar distortions resist metallization and the attendant suppression of long-range dipolar interactions in the vast majority of a sample of eleven representative ferroelectrics. We identify a novel meta-screening effect, occurring in the doped compounds as a consequence of the charge rearrangements associated to electrostatic screening, as the main factor determining the survival of a non-centrosymmetric phase. Our findings advance greatly our understanding of the essentials of structurally-polar metals, and offer guidelines on the behavior of ferroelectrics upon field-effect charge injection or proximity to conductive device elements.