title: Crystal chemistry and physical properties of the nonmagnetic Kondo compound HfAs1.7Se0.2.
abstract: Single crystals of HfAs(1.7)Se(0.2) are grown by chemical transport reaction and their chemical composition characterized in detail by various analytical methods. Chemical analyses and crystal structure investigations by single-crystal X-ray diffraction as well as powder diffraction with synchrotron radiation reveal a tetragonal PbFCl structure type with strong disorder caused by a significant arsenic deficiency (As(0.9)) on the 2a site and mixed occupancy of the 2c site (As(0.8)Se(0.2)). HfAs(1.7)Se(0.2) is a diamagnetic metal which transforms into a superconducting state at T(c)=0.52 K. Similar to other PbFCl-type arsenide selenides, the title compound displays a magnetic-field-independent -AT(1/2) term in the low-temperature electrical resistivity. This unusual term presumably originates from the electron scattering of structural two-level systems. According to the experimental results, HfAs1.7Se0.2 appears to be a rare example of a nonmagnetic Kondo material.
authors.affiliation: Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Strasse 40, Dresden, Germany. andreas.czulucki@cpfs.mpg.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Czulucki
authors.forename: Gudrun
authors.initials: G
authors.lastname: Auffermann
authors.forename: Michal
authors.initials: M
authors.lastname: Bednarski
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Bochenek
authors.forename: Maik
authors.initials: M
authors.lastname: Böhme
authors.forename: Tomasz
authors.initials: T
authors.lastname: Cichorek
authors.forename: Rainer
authors.initials: R
authors.lastname: Niewa
authors.forename: Niels
authors.initials: N
authors.lastname: Oeschler
authors.forename: Marcus
authors.initials: M
authors.lastname: Schmidt
authors.forename: Frank
authors.initials: F
authors.lastname: Steglich
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Kniep