Abstracts Book - IMRC 2018

• SD2-O011
HIGH-THROUGHPUT GENERATION OF NONPOLAR
STOICHIOMETRIC SLAB-AND-VACUUM MODELS
Yoyo Hinuma 1,2
1 Chiba University, Center for Frontier Science, Japan. 2 National Institute for Materials Science,
Division of Materials Data and Integrated System, Japan.
High-throughput first principles investigation of surface properties is impossible
without high-throughput generation of atomistic slab-and-vacuum models. Making
a nonpolar slab is very important when calculating surface energies because the
two surfaces must be identical. Moreover, the electrostatic potential at the two
sides of the slab must be the same when comparing energy levels including the
ionization potential, work function, and electron affinity, otherwise the vacuum level
becomes ill-defined. Obtaining a nonpolar and stoichiometric slab can be obvious
in some cases and could be prepared by hand, such as the rocksalt (100) surface,
but is not trivial in many crystals, especially with complicated structures.
Automatically generating nonpolar and stoichiometric slabs over a huge and
diverse set of crystals is a necessary skill when exploring the breadth of ab-initio
high-throughput surface property investigations. Although atomistic slab model
development by itself does not find exciting properties, it is a very important and
indispensable step toward discovery of novel and exciting surface physics.
Core techniques that are critical to pursue this field of research will be outlined in
the presentation, such as (1) robust and rigid definition of a nonpolar slab based on
crystallography [1], (2) quick identification of whether an orientation is always polar
or not based on the space group, (3) finding where to cleave bulk to automatically
generate a nonpolar and stoichiometric slab by simple cleaving, if possible [1], and
(4) how to automatically reconstruct the topmost and bottommost layers of a
nonpolar slab that can be made stoichiometric by removing half of the atoms at
both sides of the slab. In particular, technique (4) allows automatic generation of
nonpolar slabs of some important crystal structures, most notably perovskite and
spinel, that always require reconstruction to obtain a nonpolar and stoichiometric
slab.
[1] Hinuma et al., Comp. Mater. Sci. 113, 221 (2016)
Keywords: Slab-and-vacuum model, Polarity, High-throuput model generation
Presenting authors email: ma7s@yahoo.co.jp