alpha = {-1/2, -1/3, -1/4, 1/5, 4/7, 3/2};
beta = {-1/6, 3/7, 13/11, -2/3, 2/5, 4/3};
concavity = alpha beta (beta - 1);
origin = {-2,-0.52, -0.52, -0.025, -0.025, -0.25};
vert = {{-2,0},{-0.5,0},{-0.5,0},{0,4},{0,1},{0,4}};
ticks = {{1},{1},{1},{1},{1},{1}};
plot[k_]:= Plot[alpha[[k]]t^beta[[k]],{t,0.001,2},
		        PlotRange->{{0,2},vert[[k]]},
		        Ticks->{Table[i-1,{i,5}],Automatic},
		        AxesOrigin->{-0.1,origin[[k]]},
		        PlotLabel->N[concavity[[k]]]];
Show[GraphicsArray[Transpose[{Table[plot[i],{i,3}],Table[plot[i],{i,4,6}]}]]]