Open AccessFerroelectric Metal in Tetragonal BiCoO3/BiFeO3 Bilayers and Its Electric Field Effect
Author(s) -
Li Yin,
Wenbo Mi,
Xiaocha Wang
Publication year - 2016
Publication title -
scientific reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.24
H-Index - 213
ISSN - 2045-2322
DOI - 10.1038/srep20591
Subject(s) - ferroelectricity , tetragonal crystal system , materials science , condensed matter physics , electron , electric field , metal , polarization (electrochemistry) , ionic bonding , multiferroics , ion , dielectric , crystallography , chemistry , physics , crystal structure , optoelectronics , organic chemistry , quantum mechanics , metallurgy
By first-principles calculations we investigate the electronic structure of tetragonal BiCoO 3 /BiFeO 3 bilayers with different terminations. The multiferroic insulator BiCoO 3 and BiFeO 3 transform into metal in all of three models. Particularly, energetically favored model CoO 2 -BiO exhibits ferroelectric metallic properties, and external electric field enhances the ferroelectric displacements significantly. The metallic character is mainly associated to e g electrons, while t 2g electrons are responsible for ferroelectric properties. Moreover, the strong hybridization between e g and O p electrons around Fermi level provides conditions to the coexistence of ferroelectric and metallic properties. These special behaviors of electrons are influenced by the interfacial electronic reconstruction with formed Bi-O electrovalent bond, which breaks O A -Fe/Co-O B coupling partially. Besides, the external electric field reverses spin polarization of Fe/Co ions efficiently, even reaching 100%.