Electric-Field Control of Two-Dimensional Ferromagnetic Properties by Chiral Ionic Gating

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Chiral molecular systems offer unique ways to control spin and magnetism.
• Two-dimensional (2D) ferromagnetism in materials like FeSi(111) is sensitive to surface interactions.
• Electric-field control of magnetism is a key goal in spintronics.

Purpose of the Study:

• To investigate the use of chiral ionic liquids for electric-field modulation of 2D ferromagnetism.
• To compare the effects of chiral versus achiral ionic liquid gating on FeSi(111) thin films.
• To demonstrate chirality-induced symmetry breaking in magnetic systems.

Main Methods:

• Fabrication of FeSi(111) thin films.
• Electric double-layer transistor (EDLT) gating using both achiral and chiral ionic liquids.
• Characterization of magnetic properties, including anomalous Hall conductivity and coercive field.
• Analysis of domain magnetization ratios.

Main Results:

• Both achiral and chiral ionic liquids modulated magnetic properties like anomalous Hall conductivity and coercive field.
• Chiral ionic liquid gating, unlike achiral gating, biased the ratio of up- and down-magnetized domains in a handedness-dependent manner.
• This handedness-dependent effect provides evidence for chirality-induced symmetry breaking.

Conclusions:

• Chiral ionic liquids enable electric-field control of 2D ferromagnetism in FeSi(111) films.
• Chirality-induced symmetry breaking is demonstrated via handedness-dependent magnetic domain biasing.
• This work introduces chiral ion gating as a novel strategy for chiral spintronics.