Effects of disorder on the transport and thermoelectric properties of silicene superlattices

Abstract

Abstract Unavoidable structural disorder associated with the variation of the widths of barriers and wells as well as the heights of barriers in superlattices of 2D materials can affect considerably electronic transport and related phenomena. In this work, we study the impact of structural disorder on the electronic transport and thermoelectric properties of gated silicene superlattices (GSSLs). A low-energy effective Hamiltonian has been used to describe electrons in silicene. The transfer matrix approach, the Landauer–Buttiker formalism and the Cutler–Mott formula have been implemented to obtain the transport and thermoelectric properties. In particular, the conductance, Seebeck coefficient and power factor are investigated in ordered and disordered GSSLs. The results show that disorder related to the width of barriers-wells is not equivalent to the one associated to the height of barriers. The former barely changes the transport and thermoelectric coefficients at low energy, while the latter greatly affects them in the whole energy range. We also assess the disorder associated to the on-site potential of silicene layers, finding that its influence is limited. So, our results indicate that in the design and fabrication of GSSLs a precise control of the height of the barriers is required in order to have and preserve good thermoelectric properties.