  Directional design of functional materials with multi-objective constraints
is a big challenge, whose performance and stability are determined by different
physics factors entangled with each other complicatedly. In this work, we apply
the multi-objective optimization based on the Pareto Efficiency and
Particle-Swarm Optimization methods to design new functional materials
directionally. As a demonstration, we achieve the thermoelectric design of 2D
SnSe materials through the methods. We identify several novel metastable 2D
SnSe structures with simultaneously lower free energy and better thermoelectric
performance over the experimentally-reported monolayer structures. We hope our
results about the multi-objective Pareto Optimization method can make a step
towards the integrative design of multi-objective and multi-functional
materials in the future.
