Electrical spin injection and detection in Mn5Ge3/Ge/Mn5Ge3 nanowire transistors

Area of Science:

• Spintronics
• Semiconductor Nanowires
• Ferromagnetic Materials

Background:

• Electrical spin injection and detection are crucial for spintronic devices.
• Germanium (Ge) nanowires offer potential for novel electronic and spintronic applications.
• Conductivity mismatch between semiconductors and ferromagnets hinders efficient spin injection.

Purpose of the Study:

• To achieve electrical spin injection and detection in Ge nanowire transistors.
• To investigate spin transport properties in ferromagnetic metal/Ge nanowire heterostructures.
• To explore the potential of Ge nanowires for spintronic device applications.

Main Methods:

• Fabrication of Ge nanowire transistors with single-crystalline ferromagnetic Mn5Ge3 source/drain contacts.
• Incorporation of indium dopants for p-type conductivity in Ge nanowires.
• Measurement of magnetoresistance (MR) under varying bias and temperature.

Main Results:

• Observed negative and hysteretic MR curves indicating successful spin injection.
• Determined spin diffusion length (lsf = 480 ± 13 nm) and spin lifetime (>244 ps) at 10 K.
• Demonstrated enhanced spin transport properties in Ge nanowires compared to bulk Ge.

Conclusions:

• Electrical spin injection and detection were successfully achieved in Mn5Ge3/Ge/Mn5Ge3 nanowire transistors.
• The Elliot-Yafet mechanism dominates spin relaxation in these devices.
• These findings pave the way for Ge nanowire-based spintronic devices compatible with silicon technology.