Transport properties in ABC-ABA-ABC trilayer graphene junctions

TL;DR

This study investigates the unique electron transport properties of ABC-ABA-ABC trilayer graphene junctions, revealing Klein tunneling effects, the influence of interlayer bias, and the suppression of energy gaps under certain conditions.

Contribution

It provides a detailed analysis of transport phenomena in ABC-ABA-ABC trilayer graphene, highlighting how stacking order and external biases affect conductance and band hybridization.

Findings

Klein tunneling enables high conductance without potential barriers.

Interlayer bias induces band hybridization and reduces resonances.

Energy gap suppression occurs when both bias and potential are applied.

Abstract

Trilayer graphene {(TLG)} consists of three layers of graphene arranged in a particular stacking order. In the case of ABC-ABA-ABC stacking, the layers are arranged in an A-B-C sequence, followed by an A-B-A sequence, and again an A-B-C sequence. This stacking arrangement introduces specific electronic properties and band structures due to the different stacking configurations. We focus on elucidating the transport properties of a p-n-p junction formed with ABC-ABA-ABC stacking TLG. Employing the transfer matrix method and considering continuity conditions at the junction boundaries, we establish transmission and reflection probabilities, along with conductance. Notably, electron transport through the ABC-ABA-ABC junction exhibits Klein tunneling, resulting in substantial conductance even in the absence of a potential barrier $V_0$. This effect arises from the effective barrier induced by our specific stacking, facilitating the passage of a maximal number of electrons. However, the presence of $V_0$ diminishes Klein tunneling, leading to conductance minima. Furthermore, our findings highlight that interlayer bias $\delta$ induces a hybridization of the linear and parabolic bands of ABA-TLG within the junction, reducing resonances. In cases where $\delta\neq0$ and $V_0\neq0$, we observe a suppression of the gap, contrary to the results obtained in ABC tunneling studies where a gap exists.