Four Dimensional Stringy Black Membrane
  An exact conformal field theory describing a four dimensional singular string background is obtained by chiral gauging a $U(1)$ subgroup along with translations in $R$ of an $SL(2,R)\times R$ Wess-Zumino-Witten model. It is shown that the target space-time describes a four dimensional black membrane. Furthermore various duality transformed solutions are constructed. These are also shown to correspond to various forms of four dimensional black membranes. 
Supriya K. Kar, S. Pratik Khastgir and Gautam Sengupta