Work

A Quasi-One-Dimensional cluster vibration strategy for thermoelectric Materials: The Case of Na2AgSb

Year: 2026

Type: article

Abstract: Designing thermoelectric materials that simultaneously exhibit low lattice thermal conductivity and high electrical performance remains a challenge. Here, we propose a quasi-1D cluster-vibration strategy as a design concept. This strategy exploits collective vibrations of low-dimensional atomic clusters to enhance phonon scattering while maintaining delocalized electronic states for large power factor. To validate this concept, we selected Na 2 AgSb as a representative example and systematically investigated its transport properties using first-principles calculations combined with Boltzmann transport theory. Na 2 AgSb crystallizes into a hierarchical structure consisting of zigzag Ag-Sb chains extending along the z-axis. The collective Ag-Sb chain vibrations induce low-frequency acoustic-optical phonon coupling, reducing phonon group velocities and yielding a large Grüneisen parameter, indicative of lattice anharmonicity. Meanwhile, the delocalized electronic framework along the chain direction ensures anisotropic band edge and efficient carrier transport. This work demonstrates a promising design strategy for thermoelectric materials with intrinsically suppressed thermal transport and favorable electrical performance.

Source: Materials & Design

DOI: 10.1016/j.matdes.2026.116346