Transverse currents in spin transistors

Area of Science:

• Condensed Matter Physics
• Spintronics
• Materials Science

Background:

• The planar Hall effect, a transverse voltage from a longitudinal current, is often linked to spin-orbit coupling (SOC).
• Datta-Das spin transistors utilize SOC in a central region to control conductance via ferromagnetic leads.

Purpose of the Study:

• To investigate the emergence and characteristics of transverse currents in Datta-Das spin transistors with two-dimensional ferromagnetic reservoirs and a central SOC electron gas.
• To analyze the dependence of transverse conductivity on magnetic polarization direction and measurement location.

Main Methods:

• Theoretical modeling of charge transport in a two-dimensional electron gas with SOC, coupled to ferromagnetic reservoirs.
• Calculation of transverse and longitudinal conductivities for systems of varying widths and lengths.
• Analysis of conductivity behavior in the limit of zero longitudinal conductivity.

Main Results:

• Datta-Das spin transistors exhibit non-zero transverse conductivity.
• Transverse conductivity is dependent on the polarization direction of the ferromagnetic leads and the measurement position.
• Conductivities show Fabry-Pérot-like oscillations with variations in the SOC region length.
• Significant transverse conductivity remains even when the longitudinal conductivity is completely suppressed.

Conclusions:

• The study confirms the presence of transverse currents in Datta-Das spin transistors, driven by spin-orbit coupling.
• The findings highlight the tunability of transverse conductivity by magnetic configurations and system geometry.
• The persistence of transverse conductivity under zero longitudinal conductivity conditions suggests potential for novel spintronic applications.