The relative stability o
f multi
ferroic BiFeO
3 (0001) sur
faces, which is the (111)
facet in the pseudocubic notation, with di
fferent stoichio
metry is syste
matically studied by using
ab initio ther
modyna
mic approach in order to obtain insights into the stable sur
face ter
minations. We predict that under
most che
mical potential conditions the ther
modyna
mically
favored ter
minations
for the negative and positive sur
faces are −Bi–O
2 and −Fe–O
3–Bi, respectively. The predicted di
fference in oxygen content between the negative and positive sur
faces is consistent with experi
mental observations at the BiFeO
3/
metal inter
faces (
Nat. Mater.,
mlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:ACS="http://namespace.acs.org/2008/acs" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:space="preserve"> 2014
mlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:ACS="http://namespace.acs.org/2008/acs" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:space="preserve">, m>13m>
mlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:ACS="http://namespace.acs.org/2008/acs" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:space="preserve">, 1019, DOI:
f="http://www.nature.com/nmat/journal/v13/n11/abs/nmat4058.html" class="extLink">10.1038/nmat4058; Adv. Mater.,mlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:ACS="http://namespace.acs.org/2008/acs" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:space="preserve"> 2015mlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:ACS="http://namespace.acs.org/2008/acs" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:space="preserve">, m>27m>mlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:ACS="http://namespace.acs.org/2008/acs" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:space="preserve">, 6934, DOI: f="http://onlinelibrary.wiley.com/doi/10.1002/adma.201502754/suppinfo" class="extLink">10.1002/adma.201502754). We determine the atomic geometries and electronic states as well as the magnetic properties for the negatively and positively polarized stable surfaces. Our results demonstrate that not only the stoichiometry and atomic geometries but also the electronic and magnetic properties of the BiFeO3 (0001) surfaces show strong dependence on the ferroelectric polarization direction. Therefore, we expect that the surface physical and chemical properties of the BiFeO3 (0001) surfaces can be easily tuned by an external electric field.