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Shanmugasundaram et al. Energy Mater. 2025, 5, 500100 Energy Materials
DOI: 10.20517/energymater.2024.304

Article Open Access

Band convergence and defect engineering

synergistically revamping the carrier-phonon
dynamics in Mg Zn Sb solid solutions: an
2
3-x
x
experimental and theoretical insights

1,3
2
1,2
Priyadharshini Shanmugasundaram , Vijay Vaiyapuri , Kamalakannan Shanmugasundaram , Archana
1
4,*
Jayaram , Hiroya Ikeda , Navaneethan Mani 1,3,*
1
Centre of Excellence in Materials for Advanced Technologies (CeMAT), Faculty of Engineering and Technology, SRM Institute
of Science and Technology, Kattankulathur-603 203, India.
2
Department of Physics and Nanotechnology, SRM Institute of Science and Technology, Kattankulathur-603 203, India.
3
Nanotechnology Research Centre, Faculty of Engineering and Technology, SRM Institute of Science and Technology,
Kattankulathur-603 203, India.
4
Research Institute of Electronics, Shizuoka University, Shizuoka 432-8011, Japan.
* Correspondence to: Prof. Navaneethan Mani, Nanotechnology Research Centre, Faculty of Engineering and Technology, SRM
Institute of Science and Technology, Kattankulathur-603 203, India. E-mail: navaneem@srmist.edu.in; Prof. Hiroya Ikeda,
Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka 432-8011, Japan. E-mail:
ikeda.hiroya@shizuoka.ac.jp
How to cite this article: Shanmugasundaram, P.; Vaiyapuri, V.; Shanmugasundaram, K.; Jayaram, A.; Ikeda, H.; Mani, N. Band
convergence and defect engineering synergistically revamping the carrier-phonon dynamics in Mg Zn Sb solid solutions: an
x
3-x
2
experimental and theoretical insights. Energy Mater. 2025, 5, 500100. https://dx.doi.org/10.20517/energymater.2024.304
Received: 26 Dec 2024 First Decision: 7 Feb 2025 Revised: 28 Feb 2025 Accepted: 13 Mar 2025 Published: 13 May 2025
Academic Editor: Yuping Wu Copy Editor: Ping Zhang Production Editor: Ping Zhang

Abstract
Mg Sb -based n-type Zintl compounds have attracted greater attention for their superior thermoelectric
2
3
performance, making them a potential candidate for medium-temperature (< 900 K) applications. Herein, this
work verifies the p-type Mg Zn Sb solid-solution and defect engineering could be the key mechanism to reduce
1.8
1.2
2
the lattice thermal conductivity (κ ) for improving the thermoelectric performance. The carrier and phonon
L
transport properties were studied by adding heavy element Ag at Mg-sites of Mg Zn Sb solid-solution. As a
1.8 1.2 2
2
result, the Ag Mg Zn Sb sample simultaneously obtained the maximum power factor of 456 μW/mK via band
0.03 1.77 1.2 2
convergence and defect engineering, which led to reduced thermal conductivity of 0.56 W/mK at 753 K by the
strengthening of multiscale phonon scattering. In addition, optimized carrier density and thermal conductivity
resulting in a maximum figure of merit (zT) of 0.5 at 753 K has been obtained for Ag 0.03 Mg Zn Sb , which is 285%
2
1.77
1.2
higher than undoped Mg Zn Sb . This work demonstrates that heavy element substitution induces band
2
1.8
1.2
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