Thermodynamic Favorability of the 1T Phase over the 1H Phase in Group III Metal Monochalcogenide Zigzag Nanoribbons

Abstract

Owing to the promising optoelectronic and thermoelectric properties of two-dimensional (2D) group III-VI materials (MXs), their nanoribbons (NRs) have attracted notable attention as an emerging class of quasi-one-dimensional (quasi-1D) nanostructures. Due to the fact that the most stable 2D monolayer polymorph of MXs is the 1H phase, to date, existing studies in the literature have predominantly focused on the NRs formed from 1H phase MXs. Nevertheless, NRs of the 1T phase have received little to no attention. Employing ab initio simulations based on density functional theory, we systematically compared the thermodynamic stability of hydrogen passivated and unpassivated 1T and 1H ZNRs of GaS, GaSe, and InSe. Our results reveal that non-polar 1T phase MX ZNRs are thermodynamically more favorable than polar 1H MX ZNRs at widths up to 34 nm, a range that is realizable through contemporary experimental fabrication techniques. Furthermore, unlike metallic 1H ZNRs, 1T ZNRs remain semiconductor and retain a Mexican-hat-shaped top valence bands. Complementarily, hydrogenation energies of 1T InSe ZNRs are positive, and due to the edge-localized states, the 1T unpassivated ZNRs possess nearly flat top valence bands. Our findings serve as a compass for subsequent synthesis pathways of group III-VI NRs.

References in corpus (11)

• Energy Gaps in Graphene Nanoribbons
• High Electron Mobility, Quantum Hall Effect and Anomalous Optical Response in Atomically Thin InSe
• Electrons and phonons in single layers of hexagonal indium chalcogenides from ab initio calculations
• Energy Gaps and Stark Effect in Boron Nitride Nanoribbons
• Energy-gap modulation of boron nitride nanoribbons by transverse electric fields: First-principles calculations
• Topological phase transition in chiral graphene nanoribbons: from edge bands to end states
• Prediction of thickness limits of ideal polar ultrathin films
• Quasi-van der Waals Epitaxial Growth of γ'-GaSe Thin Films on GaAs(111)B Substrates
• Review of Nanolayered Post-transition Metal Monochalcogenides: Synthesis, Properties, and Applications
• First-principles study on the stability and electronic structure of monolayer GaSe with trigonal-antiprismatic structure
• Electric field induced injection and shift currents in zigzag graphene nanoribbons