Spin glass in semiconducting KFe$_{1.05}$Ag$_{0.88}$Te$_{2}$ single   crystals
  We report discovery of KFe$_{1.05}$Ag$_{0.88}$Te$_{2}$ single crystals with semiconducting spin glass ground state. Composition and structure analysis suggest nearly stoichiometric I4/mmm space group but allow for the existence of vacancies, absent in long range semiconducting antiferromagnet KFe$_{0.85}$Ag$_{1.15}$Te$_{2}$. The subtle change in stoichometry in Fe/Ag sublattice changes magnetic ground state but not conductivity, giving further insight into the semiconducting gap mechanism. 
Hyejin Ryu, Hechang Lei, B. Klobes, J. B. Warren, R. P. Hermann and C.   Petrovic
cond-mat.str-el cond-mat.mtrl-sci cond-mat.supr-con