title: Two-Channel Kondo Physics due to As Vacancies in the Layered Compound ZrAs_{1.58}Se_{0.39}.
abstract: We address the origin of the magnetic-field-independent -|A|T^{1/2} term observed in the low-temperature resistivity of several As-based metallic systems of the PbFCl structure type. For the layered compound ZrAs_{1.58}Se_{0.39}, we show that vacancies in the square nets of As give rise to the low-temperature transport anomaly over a wide temperature regime of almost two decades in temperature. This low-temperature behavior is in line with the nonmagnetic version of the two-channel Kondo effect, whose origin we ascribe to a dynamic Jahn-Teller effect operating at the vacancy-carrying As layer with a C_{4} symmetry. The pair-breaking nature of the dynamical defects in the square nets of As explains the low superconducting transition temperature T_{c}≈0.14  K of ZrAs_{1.58}Se_{0.39} compared to the free-of-vacancies homologue ZrP_{1.54}S_{0.46} (T_{c}≈3.7  K). Our findings should be relevant to a wide class of metals with disordered pnictogen layers.
authors.affiliation: Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-950 Wroclaw, Poland.
authors.forename: T
authors.initials: T
authors.lastname: Cichorek
authors.affiliation: Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-950 Wroclaw, Poland.
authors.forename: L
authors.initials: L
authors.lastname: Bochenek
authors.affiliation: Max-Planck-Institute for Chemical Physics of Solids, 01187 Dresden, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Schmidt
authors.affiliation: Max-Planck-Institute for Chemical Physics of Solids, 01187 Dresden, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Czulucki
authors.affiliation: Max-Planck-Institute for Chemical Physics of Solids, 01187 Dresden, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Auffermann
authors.affiliation: Max-Planck-Institute for Chemical Physics of Solids, 01187 Dresden, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Kniep
authors.affiliation: Institute of Inorganic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Niewa
authors.affiliation: Max-Planck-Institute for Chemical Physics of Solids, 01187 Dresden, Germany, Center for Correlated Matter, Zhejiang University, Hangzhou, Zhejiang 310058, China, and Institute of Physics, Chinese Academy of Science, Beijing 100190, China.
authors.forename: F
authors.initials: F
authors.lastname: Steglich
authors.affiliation: Center for Correlated Matter, Zhejiang University, Hangzhou, Zhejiang 310058, China.
authors.forename: S
authors.initials: S
authors.lastname: Kirchner