Tunable Goos--H\"anchen shifts and group delay time in single-barrier silicene

Abstract

We investigate the Goos--H\"anchen (GH) shifts and group delay time of Dirac fermions traversing a rectangular electrostatic potential barrier in silicene. By analyzing their dependence on the incident angle, barrier height, barrier width, and incident energy, we demonstrate that the GH shifts exhibit pronounced oscillations arising from quantum interference within the barrier region. The amplitude and number of oscillation peaks increase with increasing energy, barrier width, and incidence angle, resulting in enhanced lateral beam displacement. Meanwhile, the group delay time exhibits resonant features associated with the formation of quasi-bound states, increasing with barrier width, energy, and incidence angle, while decreasing with increasing barrier height. These results clarify how barrier-induced quantum interference controls both the lateral and temporal dynamics of Dirac fermions in silicene, highlighting the potential role of electrostatic barriers in enabling tunable transport in two-dimensional Dirac materials.