Final Report on 2D SpinFET on Si
Research Report Highlight
Researchers have made significant progress on 2D SpinFETs after trying many materials and devices. They have achieved high-quality ZrTe5 materials synthesized at their lab, and demonstrated the basic spin operation.
In the second half year of Year 3 and NCE Year 4 of this proposed project, we finally made significant progress on 2D SpinFETs. The main difficulty to realize 2D SpinFETs using TMD materials such as MoS2, WSe2, even TaS2 are due to the too strong spin-orbit interaction and eventually it locks spin injection and population. Many groups world wide have been exploring spin experiments on TMDs 2D materials with very limited success including our group at Purdue. Within the project, we have searched all available 2D materials including MoS2, MoSe2, WS2, WSe2, TaS2, TaSe2 and black phosphorus and fabricated at least 500 2D SpinFETs and measured at least 200 SpinFETs at low temperatures by 10 trips to National High Magnetic Field Laboratory in Tallahassee, Florida with limited progress. After many experiments on almost all different 2D materials, we realize and understand the issues related to TMDs. We have to find a 2D material having the following properties (1) near metallic so that we can have good resistance match to ferromagnetic electrodes (2) low spin-orbit interaction compared to TaS2 or TaSe2 as originally proposed (3) high-quality 2D material with high mobility so that spin diffusion length could be good enough for SpinFET. We identified self-synthesized ZrTe5 as the focused material and eventually successfully demonstrated the spin operation on ZrTe5.