Anisotropic spin motive force in multi-layered Dirac fermion system, $\alpha$-(BEDT-TTF)$_2$I$_3$

TL;DR

This paper studies the anisotropic spin motive force in a multi-layered Dirac fermion system under pressure, revealing how anisotropic interactions influence spin textures and produce measurable spin motive forces.

Contribution

It introduces a numerical analysis of anisotropic spin textures and their resulting spin motive forces in a layered Dirac fermion system, aligning theory with experimental observations.

Findings

Anisotropic interactions induce anisotropic spin order.

Calculated spin motive force matches experimental data.

Numerical method used: steepest descent.

Abstract

We investigate the anisotropic spin motive force in $\alpha$-(BEDT-TTF)$_2$I$_3$, which is a multi-layered massless Dirac fermion system under pressure. Assuming the interlayer antiferromagnetic interaction and the interlayer anisotropic ferromagnetic interaction, we numerically examine the spin ordered state of the ground state using the steepest descent method. The anisotropic interaction leads to the anisotropic spin ordered state. We calculate the spin motive force produced by the anisotropic spin texture. The result quantitatively agrees with the experiment.