Zero and controllable thermal expansion in
Li Tao1, Liu Xian-Sheng2, Cheng Yong-Guang1, 3, Ge Xiang-Hong1, Zhang Meng-Di1, Lian Hong1, Zhang Ying1, Liang Er-Jun1, †, Li Yu-Xiao1, ‡
       

(color online) Raman spectra of HfMgMo W x O12 with x = 0, 0.5, 1.0, 1.5, 2.0, 2.5, and 3 for the low wavenumber (a) and high wavenumber (b) regions, respectively. The insert shows the temperature-dependent Raman spectra of HfMgW3O12. The sharp peak denoted by an asterisk (*) is the sparkle from air plasma.