Electronic states of a correlated material can be effectively modified by structural variations delivered from a single-crystal substrate. In this letter, we show that the CrN films grown on MgO (001) substrates have a (001) orientation, whereas the CrN films on {\alpha}-Al2O3 (0001) substrates are oriented along (111) direction parallel to the surface normal. Transport properties of CrN films are remarkably different depending on crystallographic orientations. The critical thickness for the metal-insulator transition (MIT) in CrN 111 films is significantly larger than that of CrN 001 films. In contrast to CrN 001 films without apparent defects, scanning transmission electron microscopy results reveal that CrN 111 films exhibit strain-induced structural defects, e. g. the periodic horizontal twinning domains, resulting in an increased electron scattering facilitating an insulating state. Understanding the key parameters that determine the electronic properties of ultrathin conductive layers is highly desirable for future technological applications.
@article{arxiv.2103.02098,
title = {Structural Twinning-induced Insulating Phase in CrN (111) Films},
author = {Qiao Jin and Zhiwen Wang and Qinghua Zhang and Jiali Zhao and Hu Cheng and Shan Lin and Shengru Chen and Shuang Chen and Haizhong Guo and Meng He and Chen Ge and Can Wang and Jia-Ou Wang and Lin Gu and Shanmin Wang and Hongxin Yang and Kui-juan Jin and Er-Jia Guo},
journal= {arXiv preprint arXiv:2103.02098},
year = {2021}
}