Anomalous Hall effect in highly c-plane oriented Mn$_{3}$Ge/Si(100) thin films grown by pulsed laser deposition

TL;DR

This study reports the successful growth of highly oriented Mn3Ge thin films on silicon, revealing atomic-scale Kagome lattice structures and demonstrating significant anomalous Hall effects relevant for antiferromagnetic spintronics.

Contribution

First demonstration of c-plane oriented Mn3Ge thin films on Si(100) with atomic-scale Kagome lattice and measurable anomalous Hall effect.

Findings

Atomic-scale Kagome lattice observed on Mn3Ge surface

Anomalous Hall resistivity up to 0.41 μΩ·cm at 2 K

Room temperature anomalous Hall response suggests spintronic potential

Abstract

Antiferromagnetic Mn$_{3}$Ge with a non-collinear Kagome structures present exciting prospects for exploring Berry curvature driven anomalous Hall effects (AHE). Despite substantial progress in bulk systems, the synthesis of crystalline thin films directly on silicon with a hexagonal phase presents a particular challenge unless a buffer layer is employed. In this study, we report the synthesis of single phase c-plane oriented hexagonal Mn$_{3}$Ge(0001) films on Si(100) using pulsed laser deposition. Under suitable growth conditions, we obtain layer-by-layer films with atomically flat surfaces and interfaces. High-resolution scanning tunneling microscopy study reveals the detail surface atomic structures, where the surface Mn atoms spontaneously arrange into a Kagome lattice. Tunneling spectroscopy (dI/dV) measurement on the atomically resolved Kagome surface show a minima in local density of states near the Fermi level, likely originated from the Weyl crossings near K points. Despite the nearly vanishing magnetization, magnetotransport measurements in 30 nm $Mn_{3}$Ge(0001) films show anomalous Hall resistivity up to 0.41 ($\mu\Omega\cdot\text{cm}$) at 2 K. Our \textit{ab initio} calculations shed further light on the existence of topological features and the band structures in Mn$_{3+x}$Ge$_{1-x}$ with increasing Mn concentration $x$. The anomalous Hall response at room temperature in crystalline Mn$_{3}$Ge films on Si(100) offer promising potential for the development of antiferromagnetic spintronics.