First-principles comprehensive study of electronic and mechanical properties of novel uranium hydrides at different pressures

The systematic investigation on the U-H binary system up to 300 GPa has been performed by means of firstprinciples calculations in combination with the variable-composition evolutionary algorithm.Twenty uranium hydrides,including UH_x(x=1,2,3,4,5,6,7,8,9,17),U_2 H_y(y=3,5,7,13,15,17),U_3 H_8,U_3 H_(10),U4 H5 and U_4 H_9 have been found under different pressures.Besides thirteen compounds that are in nice agreement with previously reported structural search,new uranium hydrides in terms of the derived convex hull of the formation enthalpies have also been found in the present investigation.These seven novel compounds including CmcmUH_3, Fmmm-UH_4,R3 m-U_2 H_7,Pm-U_2 H_(15), Cm-U_3 H_8,C_2-U_4 H_9 and C2/m-U_4 H_5, are found to be dynamically and thermodynamically stable,and their stable pressure range has been determined.At last,the electronic and mechanical properties of these seven novel structures have further been calculated.