Remarkable band gap renormalization via dimensionality of the layered material C3B

TL;DR

This study reveals that the layered material C3B exhibits a remarkable band gap renormalization of over 2.3 eV due to interlayer effects, demonstrating its extraordinary tunability compared to similar 2D semiconductors.

Contribution

The paper provides the first detailed analysis of the layer-dependent electronic properties of C3B using advanced computational methods, highlighting its large band gap renormalization and tunability.

Findings

Bulk C3B has a quasiparticle band gap of 0.17 eV.

Monolayer C3B has a band gap of 2.55 eV.

Band gap renormalization exceeds 2.3 eV due to layering effects.

Abstract

Layer-dependent electronic and structural properties of emerging graphitic carbon boron compound C3B are investigated using both density functional theory and the GW approximation. We discover that, in contrast to a moderate quasiparticle band gap of 2.55 eV for monolayer C3B, the calculated quasiparticle band gap of perfectly stacked bulk phase C3B is as small as 0.17 eV. Therefore, our results suggest that layered material C3B exhibits a remarkably large band gap renormalization of over 2.3 eV due to the interlayer coupling and screening effects, providing a single material with an extraordinary band gap tunability. The quasiparticle band gap of monolayer C3B is also over 1.0 eV larger than that of C3N, a closely related two-dimensional semiconductor. Detailed inspections of the near-edge electronic states reveal that the conduction and valence band edges of C3B are formed by out-of-plane and in-plane electronic states, respectively, suggesting an interesting possibility of tuning the band edges of such layered material separately by modulating the in-plane and out-of-plane interactions.