Defect induced rigidity enhancement in layered semiconductors

TL;DR

This paper investigates how indium defects enhance the rigidity of layered GaSe semiconductors by increasing shear stiffness, revealing a defect-driven mechanism that could apply broadly to similar layered materials.

Contribution

It demonstrates that interstitial In defects significantly improve the shear rigidity of GaSe by altering defect formation energies and Fermi level tuning, providing a general mechanism for rigidity enhancement.

Findings

In defects increase shear stiffness in GaSe.

Fermi level tuning influences defect formation energies.

Rigidity enhancement mechanism is applicable to layered solids.

Abstract

We discuss the mechanism responsible for the observed improvement in the structural properties of In doped GaSe, a layered material of great current interest. Formation energy calculations show that by tuning the Fermi energy, In can substitute for Ga or can go as an interstitial charged defect$(\text{In}_{\text{i}}^{\text{3+}})$. We find that $\text{In}_{\text{i}}^{\text{3+}}$ dramatically increases the shear stiffness of GaSe, explaining the observed enhancement in the rigidity of In doped p-GaSe. The mechanism responsible for rigidity enhancement discussed here is quite general and applicable to a large class of layered solids with weak interlayer bonding.