High thermoelectric performances of monolayer GeTe allotropes.

IF 2.9 4区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Nanotechnology Pub Date : 2024-10-29 DOI:10.1088/1361-6528/ad88e1

L J Gong, Q Z Han, J Yang, H L Shi, Y H Ren, Y H Zhao, H Yang, Q H Liu, Z T Jiang

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引用次数: 0

Abstract

Aiming at finding wide-temperature-zone thermoelectric (TE) materials, five kinds of monolayer GeTe allotropes including the newly designedγ-,δ-, andɛ-GeTe monolayers and the usualα- andβ-GeTe ones are constructed. By using the density functional theory and the nonequilibrium Green's function method, all their electronic properties and TE transport properties are comparatively investigated. It is found that the room-temperature figure of meritZTof theγ-GeTe (ɛ-GeTe) along the armchair (zigzag) direction can amount to 4.5 (3.5), which is further increased to 7.15 (5.91) at 700 K. TheseZTvalues are much higher than the other IV-VI compounds usually withZT < 3, indicating that the armchairγ-GeTe and the zigzagɛ-GeTe we designed here can be used as superior wide-temperature-zone and high-performance TE materials in the temperature range from 300 K to 700 K. Moreover, with the increase of temperature, theZTpeaks will become wider in width and move towards the position of zero chemical potential, which will make the GeTe-based TE devices work at low bias voltages more efficiently. This work should be an important reference on the way to the stage ofZT⩾4, which will motivate more explorations into the high-performance TE materials working in a wider temperature scope.

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单层 GeTe 同素异形体的高热电性能。

为了寻找宽温区热电（TE）材料，我们构建了五种单层 GeTe 同素异形体，包括新设计的γ-、δ- 和ɛ-GeTe 单层以及常见的α- 和β-GeTe 单层。利用密度泛函理论和非平衡格林函数方法，对它们的所有电子特性和 TE 传输特性进行了比较研究。研究发现，γ-GeTe（ɛ-GeTe）沿扶手（之字形）方向的室温优点ZT值可达 4.5（3.5），在 700 K 时进一步增至 7.15（5.91）。这些 ZT 值远远高于其他通常具有 ZT γ-GeTe 的 IV-VI 化合物，我们在此设计的人字形ɛ-GeTe 可在 300 K 到 700 K 的温度范围内用作优异的宽温区高性能 TE 材料。此外，随着温度的升高，ZT 峰的宽度会变宽，并向化学势为零的位置移动，这将使基于 GeTe 的 TE 器件在低偏置电压下更高效地工作。这项工作应该是迈向 ZT⩾4 阶段的重要参考，它将激励人们对工作在更宽温度范围内的高性能 TE 材料进行更多探索。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Nanotechnology 工程技术-材料科学：综合

CiteScore

7.10

自引率

5.70%

发文量

820

审稿时长

2.5 months

期刊介绍： The journal aims to publish papers at the forefront of nanoscale science and technology and especially those of an interdisciplinary nature. Here, nanotechnology is taken to include the ability to individually address, control, and modify structures, materials and devices with nanometre precision, and the synthesis of such structures into systems of micro- and macroscopic dimensions such as MEMS based devices. It encompasses the understanding of the fundamental physics, chemistry, biology and technology of nanometre-scale objects and how such objects can be used in the areas of computation, sensors, nanostructured materials and nano-biotechnology.