problem with parfor and big sparse matrix

I have the following code but I have to run it for n>10^6. For n=10^5 the memory is over. I have 16gb. Is there any efficient way to do this?

 n = 10^6;
 m = n/2;

 H = sparse(m,n);
 parfor jj=1:n
     pos = sample(cumulative);
     H(:,jj) = (rand(m,1) > 1 - degrees(pos)/m)+0.0;     
 end