Electrical resistivity and tunneling anomalies in CeCuAs2

TL;DR

CeCuAs2 exhibits negative temperature coefficient of resistivity across a wide temperature range and shows signs of a pseudogap, suggesting it is a Kondo semiconductor with unconventional resistivity behavior.

Contribution

This study reports the first observation of negative resistivity coefficient and pseudogap features in CeCuAs2, indicating its classification as a Kondo semiconductor with unique electronic properties.

Findings

Negative resistivity coefficient from 45 mK to 300 K

Presence of a pseudogap at low temperatures

Resistivity not of an activated type

Abstract

The compound CeCuAs2 is found to exhibit negative temperature (T) coefficient of electrical resistivity (rho) under ambient pressure conditions in the entire T-range of investigation (45 mK to 300 K), even in the presence of high magnetic fields. Preliminary tunneling spectroscopic measurements indicate the existence of a psuedo-gap at least at low temperatures, thereby implying that this compound could be classified as a Kondo semi-conductor, though rho(T) interestingly is not found to be of an activated type.