Electronic structures and quantum capacitance of twisted mixed-dimensional van der Waals heterostructures of graphene/C2H based on tight-binding model

Abstract

Constructing twisted mixed dimensional graphene-based van der Waals heterostructure (vdWH) is an effective strategy to manipulate the electronic structures and improve the quantum capacitance (C _q) of graphene. In this work, mixed dimensional vdWH of graphene/C₂H has been proposed owing to similar Dirac semimetal character of one-dimensional C₂H with that of graphene. Meanwhile, the influence of twisting angle (θ) and interlayer interaction strength on the electronic structures and the C _q of the MD vdWH are systemically explored based on tight binding model. With the fitted hopping integral parameters, it is found that the linear dispersion of the graphene is basically preserved but the bandwidth is decreased with modulating twisting angle and interlayer interaction, and the C _q of mixed dimensional vdWH is improved 5–19 times compared with graphene at zero bias. Moreover, the compressed strain could enhance the C _q of mixed dimensional vdWH to 74.57 μF cm⁻² at zero bias and broaden the low working voltage window of mixed-dimensional vdWH with considerable C _q. Our results provide suitable tight-binding model parameters and theoretical guidance for exploring the twisted MD vdWH of graphene/C₂H and offer an effective strategy to modulate the electronic structures and the C _q of graphene through constructing the MD vdWH.