Phase diagram of K(x)Fe(2-y)Se(2-z)S(z) and the suppression of its superconducting state by an Fe2-Se/S tetrahedron distortion.
We report structurally tuned superconductivity in a K(x)Fe(2-y)Se(2-z)S(z) (0 ≤ z ≤ 2) phase diagram. Superconducting T(c) is suppressed as S is incorporated into the lattice, eventually vanishing at 80% of S. The magnetic and conductivity properties can be related to stoichiometry on a poorly occupied Fe1 site and the local environment of a nearly fully occupied Fe2 site. The decreasing T(c) coincides with the increasing Fe1 occupancy and the overall increase in Fe stoichiometry from z = 0 to z = 2. Our results indicate that the irregularity of the Fe2-Se/S tetrahedron is an important controlling parameter that can be used to tune the ground state in the new superconductor family.
Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
Hechang
H
Lei
Milinda
M
Abeykoon
Emil S
ES
Bozin
Kefeng
K
Wang
J B
JB
Warren
C
C
Petrovic