The impact of the near-surface region on the interpretation of x-ray absorption spectroscopy

TL;DR

This paper demonstrates how the near-surface region significantly influences the interpretation of X-ray absorption spectroscopy data in transition metal oxides, emphasizing the importance of acquisition mode selection for accurate analysis.

Contribution

It reveals the impact of surface-sensitive versus bulk-sensitive XAS modes on data interpretation in TMOs, highlighting the role of near-surface regions in electronic structure analysis.

Findings

Surface-sensitive and bulk-sensitive XAS modes yield different electronic structure insights.

Near-surface regions can cause apparent discrepancies in XAS data.

Selection of XAS mode is crucial for accurate TMO characterization.

Abstract

Transition metal oxides (TMOs) exhibit a broad spectrum of electronic, magnetic, and optical properties, making them intriguing materials for various technological applications. Soft x-ray absorption spectroscopy (XAS) is widely used to study TMOs, shedding light on their chemical state, electronic structure, orbital polarization, element-specific magnetism, and more. Different XAS acquisition modes feature different information depth regimes in the sample. Here, we employ two XAS acquisition modes, having surface-sensitive versus bulk probing depths, on the prototypical TMO SrVO3. We illustrate and elucidate a strong apparent discrepancy between the different modes, emphasizing the impact of the near-surface region on the interpretation of XAS data. These findings highlight the importance of the acquisition mode selection in XAS analysis. Moreover, the results highlight the role of the near-surface region not only in the characterization of TMOs, but also in the design of future nanoscale oxide electronics.