  We present a new method for the study of hemisystems of the Hermitian surface
$\mathcal{U}_3$ of $PG(3,q^2)$. The basic idea is to represent generator-sets
of $\mathcal{U}_3$ by means of a maximal curve naturally embedded in
$\mathcal{U}_3$ so that a sufficient condition for the existence of hemisystems
may follow from results about maximal curves and their automorphism groups. In
this paper we obtain a hemisystem in $\ PG(3,p^2)$ for each $p$ prime of the
form $p=1+16n^2$ with an integer $n$. Since the famous Landau's conjecture
dating back to 1904 is still to be proved (or disproved), it is unknown whether
there exists an infinite sequence of such primes. What is known so far is that
just $18$ primes up to $51000$ with this property exist, namely
$17,257,401,577, 1297,1601, 3137, 7057,13457,14401,15377,24337,25601,30977,$ $
32401,33857,41617,50177.$ The scarcity of such primes seems to confirm that
hemisystems of $\mathcal{U}_3$ are rare objects.
