Tunneling in ABC trilayer graphene superlattice

TL;DR

This paper investigates how varying physical parameters in ABC trilayer graphene superlattices affects electron tunneling, revealing controllable gap formation and transmission properties crucial for electronic applications.

Contribution

It introduces a detailed analysis of tunneling in ABC-TLG superlattices, highlighting the effects of parameters like cell number and barrier width on transport properties, including gap creation and conductance.

Findings

Klein tunneling decreases with more cells

Interlayer bias opens a gap and causes transmission asymmetry

Increasing barrier width and cell number enhances gaps and oscillations

Abstract

We study the transport properties of Dirac fermions in ABC trilayer graphene (ABC-TLG) superlattices. More specifically, we analyze the impact of varying the physical parameters -- the number of cells, barrier/well width, and barrier heights -- on electron tunneling in the ABC-TLG. In the initial stage, we solved the eigenvalue equation to determine the energy spectrum solutions for the ABC-TLG superlattices. Subsequently, we applied boundary conditions to the eigenspinors and employed the transfer matrix method to calculate transmission probabilities and conductance. For the two-band model, we identified the presence of Klein tunneling, with a notable decrease as the number of cells increased. The introduction of interlayer bias opened a gap as the number of cells increased, accompanied by an asymmetry in scattered transmission. Increasing the barrier/well width and the number of cells resulted in an amplified number of gaps and oscillations in both two-band and six-band cases. We observed a corresponding decrease in conductance as the number of cells increased, coinciding with the occurrence of a gap region. Our study demonstrates that manipulating parameters such as the number of cells, the width of the barrier/well, and the barrier heights provides a means of controlling electron tunneling and the occurrence of gaps in ABC-TLG. Specifically, the interplay between interlayer bias and the number of cells is identified as a crucial factor influencing gap formation and transmission asymmetry.