Our DFT calculations show that strain induced during heteroepitaxial growth can alter the anion order in thin-films of the oxynitride LaTiO₂N, large compressive strain leading to a trans order and spontaneous polarization. Strained thin films of this solar light absorber will thus suppress exciton recombination due to the internal dipolar field.
Since their coercive field is small, these materials are moreover switchable ferroelectrics, enabling turning on and off reaction pathways, which could enable photocatalysis beyond the Sabatier principle.

This work was carried out in the group of Prof. Dr. Ulrich Aschauer.

References:

• N. Vonrüti, U. Aschauer;
  "Anion Order and Spontaneous Polarization in LaTiO₂N Oxynitride Thin Films"
  Physical Review Letters, 2018, 120(4), 046001/1-5; doi:10.1103/PhysRevLett.120.046001.