Valley and spin quantum Hall conductance of silicene coupled to a ferroelectric layer
S. M. Rafi‐Ul‐Islam, Zhuo Bin Siu, Haydar Sahin, M. B. A. Jalil
Abstract
We study the quantum valley and Hall conductances in silicene coupled to a ferroelectric (FE) layer. The spin orbit interaction in silicene couples the valley, pseudospin, and real spin degrees of freedom resulting in a topological Berry curvature in the system. The finite Berry curvature in turn induces a transverse Hall conductance. In particular, if the Fermi level E f is within the bulk energy gap, the Hall conductance is quantized to integer multiples of π . We study the quantum spin and valley Hall conductivities (QSH and QVH) as functions of the applied out-of-plane electric field for different values of E f and temperature. Both conductivities vary linearly as 1/| E f | when E f is within the conduction or valence bands but reach a quantized plateau value when E f is within the bulk gap. Further, by coupling silicene to a FE layer, the QSH and QVH signals can be modulated by means of the coupling strength. This can potentially provide a robust topological memory read-out with distinct binary outputs over a wide temperature range.