Using interlayer interaction to control functional heterostructures with atomic-scale designs has become one of the most effective interface-engineering strategies nowadays. Here, we demonstrate the effect of a crystalline LaFeO3 buffer layer on amorphous and crystalline LaAlO3/SrTiO3 heterostructures. The LaFeO3 buffer layer acts as an energetically favored electron acceptor in both LaAlO3/SrTiO3 systems, resulting in modulation of interfacial carrier density and hence metal-to-insulator transition. For amorphous and crystalline LaAlO3/SrTiO3 heterostructures, the metal-to-insulator transition is found when the LaFeO3 layer thickness crosses 3 and 6 unit cells, respectively. Such different critical LaFeO3 thicknesses are explained in terms of distinct characteristic lengths of the redox-reaction-mediated and polar-catastrophe-dominated charge transfer, controlled by the interfacial atomic contact and Thomas-Fermi screening effect, respectively. Our results not only shed light on the complex interlayer charge transfer across oxide heterostructures but also provides a new route to precisely tailor the charge-transfer process at a functional interface.
@article{arxiv.2003.10677,
title = {Characteristic Lengths of Interlayer Charge-Transfer in Correlated Oxide Heterostructures},
author = {Ganesh Ji Omar and Mengsha Li and Xiao Chi and Zhen Huang and Zhi Shiuh Lim and Saurav Prakash and Shengwei Zeng and Changjian Li and Xiaojiang Yu and Chunhua Tang and Dongsheng Song and Andrivo Rusydi and Thirumalai Venkatesan and Stephen John Pennycook and Ariando Ariando},
journal= {arXiv preprint arXiv:2003.10677},
year = {2020}
}