The Effect of Mn Interstitials on the Lattice Parameter of Ga(1-x)Mn(x)As

TL;DR

This study investigates how interstitial Mn atoms affect the lattice parameter of Ga(1-x)Mn(x)As epilayers, revealing that annealing reduces Mn_I concentration and lattice parameter, with layers remaining fully strained and highly crystalline.

Contribution

It provides detailed XRD analysis of Mn interstitials' impact on lattice parameters across various Mn concentrations in GaMnAs.

Findings

Annealing decreases lattice parameter by reducing Mn_I concentration.

All samples remain fully strained and pseudomorphic to GaAs substrate.

High crystalline quality observed in both as-grown and annealed layers.

Abstract

Structural investigation of as-grown as well as annealed Ga(1-x)Mn(x)As epilayers was carried out using high resolution X-ray diffraction (XRD) measurements for a wide range of Mn concentrations (0.027<=x<=0.083), with special attention on how the interstitial Mn atoms (Mn_I) influence the lattice parameter of this material. We observe a distinct decrease of the lattice parameter after low temperature annealing of Ga(1-x)Mn(x)As, which is known to reduce the Mn_I concentration. The reciprocal space maps measured for all the investigated samples showed that the Ga(1-x)Mn(x)As layers are fully strained - i.e., they remain pseudomorphic to the GaAs (001) substrate - for the entire thickness of the samples used (in the present case over 100 nm). In all cases studied the XRD measurements revealed high crystalline perfection of both as-grown as well as annealed Ga(1-x)Mn(x)As epilayers