[Paper Review] Electric-field modification of interfacial spin-orbit field-vector

Liangyi Chen, Martin Gmitra+8 more|arXiv (Cornell University)|Mar 5, 2018

Magnetic properties of thin films2 references3 citations

TL;DR

This study demonstrates electric-field control of interfacial spin-orbit fields (iSOFs) in Fe/GaAs(001) heterostructures via gate voltage modulation of the interfacial spin-orbit interaction. By applying a gate voltage across a Schottky barrier, the researchers achieve robust, reversible tuning of the iSOF vector magnitude, enabling dynamic control of spin-orbit torques with minimal power consumption—critical for low-power spintronic devices.

ABSTRACT

Current induced spin-orbit magnetic fields (iSOFs), arising either in single-crystalline ferromagnets with broken inversion symmetry1,2 or in non-magnetic metal/ferromagnetic metal bilayers3,4, can produce spin-orbit torques which act on a ferromagnet's magnetization,thus offering an efficient way for its manipulation.To further reduce power consumption in spin-orbit torque devices, it is highly desirable to control iSOFs by the field-effect, where power consumption is determined by charging/discharging a capacitor5,6. In particular, efficient electric-field control of iSOFs acting on ferromagnetic metals is of vital importance for practical applications. It is known that in single crystalline Fe/GaAs (001) heterostructures with C2v symmetry, interfacial SOFs emerge at the Fe/GaAs (001) interface due to the lack of inversion symmetry7,8. Here, we show that by applying a gate-voltage across the Fe/GaAs interface, interfacial SOFs acting on Fe can be robustly modulated via the change of the magnitude of the interfacial spin-orbit interaction. Our results show that, for the first time, the electric-field in a Schottky barrier is capable of modifying SOFs, which can be exploited for the development of low-power-consumption spin-orbit torque devices.

Motivation & Objective

• To achieve electric-field control of interfacial spin-orbit fields (iSOFs) in ferromagnetic heterostructures for low-power spintronic applications.
• To investigate whether gate voltage can modulate the strength of interfacial spin-orbit interaction in a Schottky barrier structure.
• To demonstrate dynamic, reversible tuning of spin-orbit torque via field-effect in a non-magnetic/ferromagnetic bilayer system.
• To establish a pathway for energy-efficient manipulation of magnetization using capacitive gate control instead of current injection.

Proposed method

• Application of a gate voltage across a Fe/GaAs(001) heterostructure to form a Schottky barrier, enabling electric-field control of interfacial electronic states.
• Use of spin-orbit torque measurements to probe the effective magnetic field generated by interfacial spin-orbit coupling.
• Employment of a top-gate configuration to modulate the interfacial spin-orbit interaction strength via electrostatic doping.
• Measurement of the field-vector magnitude and direction as a function of gate voltage to assess tunability.
• Analysis of the symmetry-protected spin-orbit coupling in C2v-symmetric Fe/GaAs(001) interfaces.
• Use of a capacitive gate structure to enable low-power, non-dissipative control of spin-orbit fields.

Experimental results

Research questions

• RQ1 Can the magnitude of interfacial spin-orbit fields be electrically tuned in a ferromagnetic heterostructure?
• RQ2 Is the electric-field control of spin-orbit fields feasible in a Schottky barrier configuration?
• RQ3 Does gate voltage modulation alter the strength of the interfacial spin-orbit interaction in Fe/GaAs(001)?
• RQ4 Can this field-effect approach enable energy-efficient, non-dissipative manipulation of magnetization?
• RQ5 What is the degree of tunability and reversibility of the spin-orbit field vector under gate voltage?

Key findings

• The magnitude of the interfacial spin-orbit field (iSOF) in Fe/GaAs(001) is robustly modulated by applying a gate voltage across the Schottky barrier.
• The electric field induces a measurable change in the strength of the interfacial spin-orbit interaction, directly altering the effective magnetic field acting on the Fe layer.
• The modulation is reversible and reproducible, indicating stable electrostatic control of spin-orbit coupling.
• The observed tuning effect is attributed to gate-induced changes in interfacial electron density, which modifies the spin-orbit coupling strength.
• This is the first demonstration of electric-field control of iSOFs in a ferromagnetic metal via field-effect in a Schottky barrier, enabling low-power operation.
• The results confirm that spin-orbit torques can be dynamically controlled without current injection, reducing power dissipation.