AUTHOR=Rafi-Ul-Islam S. M. , Siu Zhuo Bin , Sahin Haydar , Jalil Mansoor B. A. 

TITLE=Valley and spin quantum Hall conductance of silicene coupled to a ferroelectric layer

JOURNAL=Frontiers in Physics

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2022.1021192

DOI=10.3389/fphy.2022.1021192

ISSN=2296-424X

ABSTRACT=<p>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 <italic>E</italic><sub><italic>f</italic></sub> is within the bulk energy gap, the Hall conductance is quantized to integer multiples of <italic>π</italic>. 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 <italic>E</italic><sub><italic>f</italic></sub> and temperature. Both conductivities vary linearly as 1/|<italic>E</italic><sub><italic>f</italic></sub>| when <italic>E</italic><sub><italic>f</italic></sub> is within the conduction or valence bands but reach a quantized plateau value when <italic>E</italic><sub><italic>f</italic></sub> 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.</p>