Two-Channel Kondo Physics due to As Vacancies in the Layered Compound ZrAs_{1.58}Se_{0.39}

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Chemistry

Background:

• The magnetic-field-independent -|A|T^{1/2} term in low-temperature resistivity is observed in As-based PbFCl-type metals.
• Understanding the origin of this anomaly is crucial for materials with potential electronic applications.

Purpose of the Study:

• To investigate the origin of the low-temperature resistivity anomaly in As-based metallic systems.
• To elucidate the role of vacancies in the observed transport properties and superconductivity.

Main Methods:

• Experimental investigation of the layered compound ZrAs_{1.58}Se_{0.39}.
• Analysis of low-temperature transport anomalies and superconducting transition temperatures.
• Theoretical consideration of the two-channel Kondo effect and dynamic Jahn-Teller effect.

Main Results:

• Vacancies in the square nets of arsenic (As) layers are identified as the cause of the low-temperature transport anomaly.
• The anomaly is attributed to the nonmagnetic two-channel Kondo effect, originating from a dynamic Jahn-Teller effect at C_{4} symmetric As sites.
• The presence of these dynamical defects significantly reduces the superconducting transition temperature (T_{c}) from ~3.7 K in ZrP_{1.54}S_{0.46} to ~0.14 K in ZrAs_{1.58}Se_{0.39}.

Conclusions:

• Defects in pnictogen layers, specifically arsenic vacancies, are responsible for low-temperature resistivity anomalies and reduced superconductivity in PbFCl-type metals.
• The findings provide a mechanism for understanding transport properties in disordered metallic systems.
• This research is relevant to a broad range of metals containing disordered pnictogen layers.