# Optimized spin-injection efficiency and spin MOSFET operation based on low-barrier ferromagnet/insulator/n-Si tunnel contact

## TL;DR

This paper theoretically analyzes how low-barrier ferromagnet/insulator/n-Si tunnel contacts can enhance spin injection efficiency and enable effective spin MOSFET operation, highlighting the potential of TiO2 and Ta2O5 barriers.

## Contribution

It demonstrates that low-barrier materials like TiO2 and Ta2O5 improve spin injection and MR ratio, with tunable spin asymmetry coefficients, expanding the design space for spintronic devices.

## Key findings

- Low-resistance tunnel contacts with TiO2 and Ta2O5 improve spin injection.
- TiO2 exhibits negative spin asymmetry coefficient.
- Ta2O5's spin asymmetry can be tuned between positive and negative.

## Abstract

We theoretically investigate the spin injection in different FM/I/n-Si tunnel contacts by using the lattice NEGF method. We find that the tunnel contacts with low barrier materials such as TiO$_2$ and Ta$_{2}$O$_{5}$, have much lower resistances than the conventional barrier materials, resulting in a wider and attainable optimum parameters window for improving the spin injection efficiency and MR ratio of a vertical spin MOSFET. Additionally, we find the spin asymmetry coefficient of TiO$_2$ tunnel contact has a negative value, while that of Ta$_{2}$O$_{5}$ contact can be tuned between positive and negative values, by changing the parameters.