Helical dislocation-driven plasticity and flexible high-performance thermoelectric generator in α-Mg3Bi2 single crystals

Mingyuan Hu; Jianmin Yang; Yan Wang; Junchao Xia; Quan Gan; Shuhuan Yang; Juping Xu; Shulin Liu; Wen Yin; Baohai Jia; Lin Xie; Haifeng Li; Jiaqing He

doi:10.1038/s41467-024-55689-7

Helical dislocation-driven plasticity and flexible high-performance thermoelectric generator in α-Mg₃Bi₂ single crystals

Nat Commun. 2025 Jan 2;16(1):128. doi: 10.1038/s41467-024-55689-7.

Authors

Mingyuan Hu^#^{1

2}, Jianmin Yang^#¹, Yan Wang^#¹, Junchao Xia^{1

3}, Quan Gan¹, Shuhuan Yang^{1

3}, Juping Xu⁴, Shulin Liu⁴, Wen Yin⁴, Baohai Jia¹, Lin Xie¹, Haifeng Li³, Jiaqing He^{5

6}

Affiliations

¹ Shenzhen Key Laboratory of Thermoelectric Materials, Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China.
² Guangdong Provincial Key Laboratory of Advanced Thermoelectric Materials and Device Physics, Southern University of Science and Technology, Shenzhen, 518055, China.
³ Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macao SAR, 999078, China.
⁴ Spallation Neutron Source Science Center, Dongguan, 523803, China.
⁵ Shenzhen Key Laboratory of Thermoelectric Materials, Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China. [email protected].
⁶ Guangdong Provincial Key Laboratory of Advanced Thermoelectric Materials and Device Physics, Southern University of Science and Technology, Shenzhen, 518055, China. [email protected].

^# Contributed equally.

Abstract

Inorganic plastic semiconductors play a crucial role in the realm of flexible electronics. In this study, we present a cost-effective plastic thermoelectric semimetal magnesium bismuthide (α-Mg₃Bi₂), exhibiting remarkable thermoelectric performance. Bulk single-crystalline α-Mg₃Bi₂ exhibits considerable plastic deformation at room temperature, allowing for the fabrication of intricate shapes such as the letters "SUSTECH" and a flexible chain. Transmission electron microscopy, time-of-flight neutron diffraction, and chemical bonding theoretic analyses elucidate that the plasticity of α-Mg₃Bi₂ stems from the helical dislocation-driven interlayer slip, small-sized Mg atoms induced weak interlayer Mg-Bi bonds, and low modulus of intralayer Mg₂Bi₂^2- networks. Moreover, we achieve a power factor value of up to 26.2 µW cm^-1 K^-2 along the c-axis at room temperature in an n-type α-Mg₃Bi₂ crystal. Our out-of-plane flexible thermoelectric generator exhibit a normalized power density of 8.1 μW cm^-2 K^-2 with a temperature difference of 7.3 K. This high-performance plastic thermoelectric semimetal promises to advance the field of flexible and deformable electronics.