Electronic Properties and Stacking Ordering in Layered GeTe-Rich (GeTe) m (Sb2Te3) n

TL;DR

This paper studies how annealing affects the structure and electronic properties of GeTe-rich alloys, revealing insights into their stacking order and vacancy arrangement.

Contribution

The study provides new insights into vacancy ordering and stacking changes in GeTe-rich alloys due to annealing.

Findings

Annealing induces compositional and structural changes in GeTe-rich alloys.

Residual defects influence the stacking order of the epilayers.

Findings are relevant for memory applications and ferroelectricity in these materials.

Abstract

In this work, a study
of the structural and electronic properties
of epitaxial GeTe-rich (GeTe)
m
(Sb2Te3)
n
alloys grown
on Si substrate by molecular beam epitaxy is presented, with particular
focus on the effects of annealing at increasing temperatures. The
samples, displaying a lamellar structure stabilized by epitaxy, were
investigated by X-ray diffraction and X-ray photoemission spectroscopy
after heating in ultra-high vacuum. The combined use of these techniques,
supported by density functional theory calculations, reveals compositional
and structural changes induced by annealing, clarifying how the rearrangement
of residual defects influences the stacking order of the epilayers.
These results provide key insights into the vacancy ordering of GeTe-rich
(GeTe)
m
(Sb2Te3)
n
, which are particularly relevant not only
for memory applications but also in light of the recent discovery
of (GeTe)
m
(Sb2Te3)
n
ferroelectricity.

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