@article{chen_ahmadi-majlan_lim_zhang_ngai_kumah_2022, title={Effect of buffer termination on intermixing and conductivity in LaTiO3/SrTiO3 heterostructures integrated on Si(100)}, volume={40}, ISSN={["1520-8559"]}, url={https://doi.org/10.1116/6.0001464}, DOI={10.1116/6.0001464}, abstractNote={The control of chemical exchange across heterointerfaces formed between ultrathin functional transition-metal oxide layers provides an effective route to manipulate the electronic properties of these systems. By determining the layer-resolved structural profile across the interface between the Mott insulator, LaTiO3 (LTO) grown epitaxially on SrTiO3 (STO)-buffered silicon by molecular beam epitaxy, we find that interfacial cationic exchange depends on the surface termination of the strained STO buffer. Using a combination of temperature-dependent transport and synchrotron x-ray crystal truncation rods and reciprocal space mapping, an enhanced conductivity in STO/LTO/SrO-terminated STO buffers compared to heterostructures with TiO2-terminated STO buffers is correlated with La/Sr exchange and the formation of metallic La1−xSrxTiO3. La/Sr exchange effectively reduces the strain energy of the system due to the large lattice mismatch between the nominal oxide layers and the Si substrate.}, number={1}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Chen, Tongjie and Ahmadi-Majlan, Kamyar and Lim, Zheng Hui and Zhang, Zhan and Ngai, Joseph H. and Kumah, Divine P.}, year={2022}, month={Jan} }
 @article{chen_ahmadi-majlan_lim_zhang_ngai_kemper_kumah_2018, title={Interfacial structure of SrZrxTi1−xO3 films on Ge}, volume={113}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.5046394}, DOI={10.1063/1.5046394}, abstractNote={The interfacial structure of SrZrxTi1−xO3 films grown on semiconducting Ge substrates is investigated by synchrotron X-ray diffraction and first-principles density functional theory. By systematically tuning the Zr content x, the effects of bonding at the interface and epitaxial strain on the physical structure of the film can be distinguished. The interfacial perovskite layers are found to be polarized as a result of cation-anion ionic displacements perpendicular to the perovskite/semiconductor interface. We find a correlation between the observed buckling and valence band offsets at the SrZrxTi1−xO3/Ge interface. The trends in the theoretical valence band offsets as a function of Zr content for the polar structures are in agreement with reported X-ray photoelectron spectroscopy measurements. These results have important implications for the integration of functional oxide materials with established semiconductor based technologies.}, number={20}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Chen, Tongjie and Ahmadi-Majlan, Kamyar and Lim, Zheng Hui and Zhang, Zhan and Ngai, Joseph H. and Kemper, Alexander F. and Kumah, Divine P.}, year={2018}, month={Nov}, pages={201601} }