The role of resonant bonding in governing the thermal transport properties of two-dimensional black phosphorus

TL;DR

This paper investigates how resonant bonding influences the thermal transport properties of phosphorene, revealing that long-range interactions and phonon anharmonicity driven by orbital states are key to understanding heat flow in this 2D material.

Contribution

It provides the first detailed analysis of resonant bonding's role in phonon transport and anharmonicity in phosphorene, linking electronic structure to thermal properties.

Findings

Resonant bonding in phosphorene causes long-range interactions.

Strong phonon anharmonicity is linked to soft TO phonon modes.

Orbital-driven resonant bonding influences phonon transport.

Abstract

Fundamental insight into lattice dynamics and phonon transport is critical to the efficient manipulation of heat flow, which is one of the appealing thermophysical problems with enormous practical implications. Phosphorene, a novel elemental two-dimensional (2D) semiconductor with high carrier mobility and intrinsically large direct band gap, possesses fascinating chemical and physical properties distinctively different from other 2D materials. The rapidly growing applications of phosphorene in nano-/opto-electronics and thermoelectrics call for fundamental understanding of the thermal transport properties. In this study, based on the analysis of electronic structure and lattice dynamics, we demonstrate the formation of resonant bonding in phosphorene. Fundamental insight into the thermal transport in phosphorene is provided by discussing the role of resonant bonding in driving long-range interactions and strong phonon anharmonicity. We reveal that the strong phonon anharmonicity is associated with the soft transverse optical (TO) phonon modes and arises from the long-range interactions driven by the orbital governed resonant bonding. Our study highlights the physical origin of the phonon anharmonicity in phosphorene, and also provides new insights into phonon transport from the view of orbital states, which would be of great significance to the design and development of high-performance phosphorene based nano-devices.