S r 2 Ir O 4 is a spin-orbit-coupled insulator with an antiferromagnetic (AFM) transition at TN=
240 K. We report results of a comprehensive study of single-crystal S r 2 I r 1− x T bx O 4
(0≤ x≤ 0.03). This study found that a mere 3%(x= 0.03) of tetravalent T b 4+(4 f 7)
substituting for I r 4+(rather than S r 2+) completely suppresses the long-range collinear AFM
transition but retains the insulating state, leading to a phase diagram featuring a decoupling
of the magnetic interactions and charge gap. The insulating state at x= 0.03 is characterized …

We report results of a comprehensive study of single-crystal Sr 2 Ir 1-x Tb x O 4 (0<= x<=
0.03). This study found that mere 3%(x= 0.03) tetravalent Tb4+ substituting for Ir4+(rather
than Sr2+) completely suppresses the long-range collinear AFM transition but retains the
insulating state. Tb doping effectively changes the relative strength of the SOI and the
tetragonal CEF and enhances the Hund's rule coupling that competes with the SOI, and
destabilizes the AFM state. We observe unconventional correlation between the AFM and …