Anomalous hybridization complementation effect on phonon transport in heterogeneous nanowire cross junction

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Phonon transport in nanostructures is crucial for thermal management.
• Controlling wave nature of phonons offers unique thermal properties.
• Nano cross junctions (NCJs) are promising for thermal manipulation.

Purpose of the Study:

• To investigate thermal conductivity of heterogeneous nano cross junctions (hetero-NCJs).
• To explore the effect of atomic mass variation in side wires (SWs) on thermal transport.
• To understand the underlying mechanisms of thermal conductivity modulation in hetero-NCJs.

Main Methods:

• Molecular dynamics (MD) simulations were employed to study thermal conductivity.
• Non-equilibrium Green's function (NEGF) calculations were performed for mechanistic analysis.
• Systematic variation of atomic mass in SWs of hetero-NCJs.

Main Results:

• Decreasing or increasing SW atomic mass enhanced thermal conductivity compared to homogeneous NCJs (homo-NCJs).
• An abnormal decrease in thermal conductivity was observed with mixed SW atomic masses, falling below homo-NCJ values.
• Unidirectional shift of resonant modes broke hybridization, increasing conductivity; bidirectional shift complemented hybridization, blocking phonon transport.

Conclusions:

• Atomic mass manipulation in SWs provides a tunable mechanism for thermal conductivity control in hetero-NCJs.
• Resonant hybridization plays a key role in modulating phonon transport, offering pathways for thermal management.
• This study presents a method to strengthen resonant hybridization for advanced thermal transport manipulation.