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Covalent effects in magnetic ferroelectrics Mn M O 3 ( M = Ti, Sn)
Author(s) -
Hao Xianfeng,
Xu Yuanhui,
Franchini Cesare,
Gao Faming
Publication year - 2015
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201451476
Subject(s) - ferroelectricity , antiferromagnetism , condensed matter physics , density functional theory , materials science , covalent bond , atom (system on chip) , computational chemistry , physics , chemistry , dielectric , quantum mechanics , optoelectronics , computer science , embedded system
By means of first‐principles calculations based on density functional theory (DFT), DFT + U and hybrid functional methods, we report a comparative study of the magnetic, electronic, and ferroelectric properties of high‐pressure‐induced compounds Mn M O 3 ( M = Ti, Sn). The results correctly describe the insulating character and G‐type antiferromagnetic ground state for both compounds, which is in good agreement with the experimental observations. We predicted large spontaneous ferroelectric polarizations of MnTiO 3 and MnSnO 3 by using the Berry‐phase method. In particular, the proper covalent interaction mechanism driving the ferroelectric transition is discussed and explained in term of the analysis of potential‐energy surfaces, Born effective charges, and electric localization function. Our results indicate that MnTiO 3 and MnSnO 3 represent unique examples of ferroelectric perovskites in which the ferroelectric instabilities originate from the combined action of geometric effects and chemical activity of the B‐site atom, thus extending the concept of d 0 ‐ness (MnTiO 3 ) and lone‐pair mechanism (MnSnO 3 ) to magnetic ferroelectrics.