On Salem numbers which are exceptional units II

Abstract

We show that for any natural number $n$ satisfying $n\equiv 4 \mod 8$ and $n\not\equiv 0 \mod 5$, and for any odd integer $t\geq \frac{n+6}{2}$ there are infinitely many Salem numbers $α$ of degree $2t$ such that $α^n-1$ is a unit. This result, obtained using a generalization of a construction due to Gross and McMullen [5], partially completes the main result of [7].