Transition Metal and Vacancy Defect Complexes in Phosphorene: A Spintronic Perspective

TL;DR

This study investigates how transition metals interact with pristine and defected phosphorene, revealing that defect sites stabilize metals and induce magnetic moments, which are promising for spintronic applications.

Contribution

It provides a detailed microscopic analysis of transition metal absorption on phosphorene, highlighting the role of defects in stabilizing metals and inducing magnetism for spintronics.

Findings

Defects anchor metals and reduce diffusivity, enabling controlled magnetism.

Transition metal complexes retain semiconducting properties while gaining magnetic moments.

Divacancies are more thermodynamically stable than monovacancies, crucial for practical applications.

Abstract

Inducing magnetic moment in otherwise nonmagnetic two-dimensional semiconducting materials is the key first step to design spintronic materials. Here, we study the absorption of transition-metals on pristine and defected single-layer phosphorene, within density functional theory. We predict that increased transition-metal diffusivity on pristine phosphorene would hinder any possibility of controlled magnetism, and thus any application. In contrast, the point-defects will anchor metals, and exponentially reduce the diffusivity. Similar to other two-dimensional materials, metals bind strongly on both pristine and defected phosphorene, and we provide a microscopic description of bonding, which explain the qualitative trend with increasing number of valence electrons. We further argue that the divacancy complex is imperative in any practical purpose due to their increased thermodynamic stability over monovacancy. For most cases, the defect-transition metal complexes retain the intrinsic semiconduction properties, and also induce a local magnetic moment with large exchange-splitting and spin-flip energies, which are necessary for spintronic applications. Specifically, the V/Mn/Fe absorbed at the divacancy have tremendous promise in this regard. Further, we provide a simple microscopic model to describe the local moment formation in these transition metal and defect complexes.