Issue 35, 2023

Lattice anharmonicity in charge compensated higher manganese silicide single crystals

Abstract

Lattice anharmonicity driven by weakening interatomic interactions inherits an intrinsically low lattice thermal conductivity in a crystal. In this work, we demonstrate the efficacy of V (hole-doping) and Fe (electron-doping) co-substitutions on the Mn-sites for realizing charge compensation and lattice anharmonicity in p-type higher manganese silicide (HMS) single crystals melt grown employing the Bridgman method. A higher power factor sustained by optimal valence electron count (VEC) through charge compensation along with a significant reduction in lattice thermal conductivity promoted by local ordering or atomic clustering-induced lattice anharmonicity has enabled the attainment of an unprecedentedly higher thermoelectric figure-of-merit (zT) ∼0.75 (±0.1) at 873 K in partially substituted (Mn0.94V0.03Fe0.03)Si1.74 single crystals, corresponding to ∼300% enhancement over pristine MnSi1.74. The inherent structural modulation and incommensurate periodicities were assessed employing the Le Bail analysis within the framework of a (3 + 1)-dimensional superspace approach and interpreted by following the 14-electron rule for Nowotny chimney ladder phases to reveal the structure–property correlations. These findings provide a greater understanding of the interrelations between crystal structure, chemical bonding, and lattice dynamics in HMSs, a prominent example of the Nowotny chimney ladder phase for thermoelectric applications.

Graphical abstract: Lattice anharmonicity in charge compensated higher manganese silicide single crystals

  • This article is part of the themed collection: #MyFirstJMCA

Supplementary files

Article information

Article type
Paper
Submitted
20 May 2023
Accepted
14 Aug 2023
First published
14 Aug 2023

J. Mater. Chem. A, 2023,11, 19107-19117

Lattice anharmonicity in charge compensated higher manganese silicide single crystals

N. S. Chauhan, I. Ono and Y. Miyazaki, J. Mater. Chem. A, 2023, 11, 19107 DOI: 10.1039/D3TA02985A

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