Conductance due to the Edge Modes in Nanoribbons of 2D Materials in a Topological Phase

Employing novel 2D materials with topologically protected current-carrying edge states is promising to boost the on-current in electronic devices. Using nanoribbons is essential to reduce the contribution of the 2D bulk states to the current. Making the nanoribbon widths narrower allows one to put more current-carrying edge states under the gate of a fixed width thus boosting the current. However, the edge states start to interact in narrow nanoribbons. Based on an effective k·p model, we analyze the topologically protected edge states and their conductance for several 2D materials as a function of the normal electric field. We compare the 2D materials MoS
2
, MoSe
2
, WS
2
, and WSe
2
in the topological 1T′ phase and find the largest electric field-induced conductance modulation is in MoS
2
nanoribbons.