(2 + 1)-D spatial ring solitons in a semiconductor quantum well system Jibing Liu, Tangkun Liu, Hong Li, Xiao-Tao Xie, D. N. Wang and Ray-Kuang Lee EPL, 112 5 (2015) 56002 Published online: 21 December 2015 DOI: 10.1209/0295-5075/112/56002