First-Principles Study of Structural and Electronic Properties of Germanene

TL;DR

This study uses first-principles calculations to explore the structural and electronic properties of germanene, revealing a buckled honeycomb structure and electronic similarities to graphene, along with new predictions about in-plane contraction under stretching.

Contribution

It provides the first detailed first-principles analysis of germanene's structure and electronic properties, including novel predictions about its in-plane contraction behavior.

Findings

Germanene has a buckled honeycomb structure with a buckling parameter of 0.635 Å.

Germanene's electronic structure is similar to that of graphene.

Predicted in-plane contraction of germanene during thermal stretching along the c-axis.

Abstract

The ground state structural and electronic properties of germanene (the germanium analogue of graphene) are investigated using first-principles calculations. On structure optimization, the graphene-like honeycomb structure of germanene turns out as buckled (buckling parameter $\Delta = 0.635$ \AA) in contrast with graphene's planar structure (buckling parameter $\Delta = 0.0$ \AA). In spite of this, germanene has similar electronic structure as that of graphene. While corroborating the reported results, we newly predict the in-plane contraction of hexagonal Ge with (thermal) stretching along the "c" axis, akin to a phenomenon observed in graphite.