Charge density functional plus U calculation of lacunar spinel GaM4Se8(M = Nb, Mo, Ta, and W) Hyunggeun Lee, Min Yong Jeong, Jae-Hoon Sim, Hongkee Yoon, Siheon Ryee and Myung Joon Han EPL, 125 4 (2019) 47005 Published online: 25 March 2019 DOI: 10.1209/0295-5075/125/47005