Highly Efficient Spin-to-Charge Current Conversion in Strained HgTe Surface States Protected by a HgCdTe Layer.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Spin-to-charge conversion is a key phenomenon in spintronics.
• Mercury telluride (HgTe) and its alloys offer unique electronic properties due to their band structure.
• Understanding conversion mechanisms is crucial for developing novel electronic devices.

Purpose of the Study:

• To investigate spin-to-charge current conversion in strained mercury telluride (HgTe) at room temperature.
• To explore the role of a mercury cadmium telluride (HgCdTe) barrier in enhancing conversion efficiency.
• To elucidate the underlying physical mechanisms responsible for the observed conversion rates.

Main Methods:

• Utilizing spin pumping experiments to generate spin currents.
• Employing strained HgTe layers with a protective HgCdTe barrier.
• Measuring conversion efficiency and inverse Edelstein lengths.
• Analyzing the temperature dependence of resistivity.

Main Results:

• Observed significant spin-to-charge current conversion in strained HgTe at room temperature.
• Achieved high conversion rates with inverse Edelstein lengths up to 2.0±0.5 nm using a HgCdTe barrier.
• Demonstrated that HgTe layer thickness influences conversion efficiency differently than predicted by spin Hall effect models.
• Correlated high conversion rates with the spin momentum locking property of HgTe surface states.

Conclusions:

• The study confirms efficient spin-to-charge conversion in strained HgTe at room temperature.
• The HgCdTe barrier effectively protects HgTe and enhances conversion rates, attributed to spin momentum locking.
• The findings suggest HgTe surface states are a promising platform for spintronic applications.