Copper migration and surface oxidation of $\text{Cu}_{x}\text{Bi}_2\text{Se}_3$ in ambient pressure environments

Adam L. Gross; Lorenz Falling; Matthew C. Staab; Metzli I. Montero; Rahim R. Ullah; David M. Nisson; Peter Klavins; Kristie J. Koski; Nicholas J. Curro; Valentin Taufour; Slavomir Nemsak; Inna M. Vishik

arXiv · 2207.04155

Copper migration and surface oxidation of $\text{Cu}_{x}\text{Bi}_2\text{Se}_3$ in ambient pressure environments

Adam L. Gross·Lorenz Falling·Matthew C. Staab·Metzli I. Montero·Rahim R. Ullah·David M. Nisson·Peter Klavins·Kristie J. Koski·Nicholas J. Curro·Valentin Taufour·Slavomir Nemsak·Inna M. Vishik

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Abstract

Chemical modifications such as intercalation can be used to modify surface properties or to further functionalize the surface states of topological insulators. Using ambient pressure X-ray photoelectron spectroscopy, we report copper migration in $\text{Cu}_{x}\text{Bi}_2\text{Se}_3$, which occurs on a timescale of hours to days after initial surface cleaving. The increase in near-surface copper proceeds along with the oxidation of the sample surface and large changes in the selenium content. These complex changes are further modelled with core-level spectroscopy simulations, which suggest a composition gradient near the surface which develops with oxygen exposure. Our results shed light on a new phenomenon that must be considered for intercalated topological insulators$\unicode{x2014}$and intercalated materials in general$\unicode{x2014}$that surface chemical composition can change when specimens are exposed to ambient conditions.

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Adam L. Gross, Lorenz Falling, Matthew C. Staab, Metzli I. Montero, Rahim R. Ullah, David M. Nisson, Peter Klavins, Kristie J. Koski, Nicholas J. Curro, Valentin Taufour, Slavomir Nemsak, Inna M. Vishik. 2022-07-08. Copper migration and surface oxidation of $\text{Cu}_{x}\text{Bi}_2\text{Se}_3$ in ambient pressure environments. https://arxiv.org/abs/2207.04155

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