$gl(2|2)$ Current Superalgebra and Non-unitary Conformal Field Theory
  Motivated by application of current superalgebras in the study of disordered systems such as the random XY and Dirac models, we investigate $gl(2|2)$ current superalgebra at general level $k$. We construct its free field representation and corresponding Sugawara energy-momentum tensor in the non-standard basis. Three screen currents of the first kind are also presented. 
Xiang-Mao Ding, Mark D. Gould and Yao-Zhong Zhang