In collaboration with Prof. Kageshima (Shimane University).
I provide theoretical and computational support for studies of silicon-based quantum devices by using first-principles (DFT) calculations to identify microscopic mechanisms behind device-specific phenomena. In one collaboration, we focused on the giant valley splitting observed in silicon-on-insulator structures with a buried oxide (BOX), where direct experimental access to the relevant buried interface is limited.
My main contribution was to show that interfacial strain at the Si/SiO2 interface is a plausible origin of the giant valley splitting. By comparing strained and unstrained Si quantum slab models in first-principles calculations, we found that strain (notably along the [110] direction) can strongly enhance the valley splitting, supporting a strain-driven mechanism consistent with the fabrication scenario and interface-quality dependence.