Comment on "Correlation between Bulk Thermodynamic Measurements and the Low-Temperature-Resistance Plateau in SmB6"

TL;DR

This paper critiques a recent study on SmB6, arguing that its claims about surface valence changes are not supported by the spectroscopic data, emphasizing the importance of accurate interpretation of thermodynamic and spectroscopic measurements.

Contribution

It provides a critical analysis showing that previous claims of surface valence change in SmB6 are not substantiated by the spectroscopic evidence presented.

Findings

The previous report's claims are not supported by x-ray absorption spectroscopy data.

Surface conduction in SmB6 is confirmed to be due to surface, not bulk, effects.

The critique emphasizes careful interpretation of spectroscopic results in surface studies.

Abstract

Low-temperature-resistivity plateau observed in $\rm SmB_6$ single crystal,which is due to surface, not bulk, conduction has been confirmed from electrical transport measurements. Recently, the correlation between bulk thermodynamic measurements and the low-temperature-resistance plateau in $\rm SmB_6$ have been investigated and a change in Sm valence at the surface has been obtained from x-ray absorption spectroscopy and x-ray magnetic circular dichroism. Here we show that the statement of the report are not supported by the results from x-ray absorption spectroscopy and x-ray magnetic circular dichroism.