New Phases of Germanene

TL;DR

This paper introduces new stable phases of germanene formed by dumbbell structures, revealing diverse electronic and magnetic properties, and details the spontaneous formation and interactions of Ge adatoms on germanene.

Contribution

It demonstrates the spontaneous formation of dumbbell structures on germanene and proposes new stable phases with varied electronic and magnetic properties.

Findings

Dumbbell structures form spontaneously on germanene.

High coverage of dumbbells leads to new stable phases.

These phases exhibit diverse electronic and magnetic behaviors.

Abstract

Germanene, a graphene like single layer structure of Ge, has been shown to be stable and recently grown on Pt and Au substrates. We show that a Ge adatom adsorbed to germanene pushes down the host Ge atom underneath and forms a dumbbell structure. This exothermic process occurs spontaneously. The attractive dumbbell-dumbbell interaction favors high coverage of dumbbells. This letter heralds stable new phases of germanene, which are constructed from periodically repeating coverage of dumbbell structures and display diversity of electronic and magnetic properties.