Engineering Thermoelectric Performance of α-GeTe by Ferroelectric Distortion
Yuting Fan , Chenghao Xie , Jun Li , Xiangyu Meng , Jinchang Sun , Jinsong Wu , Xinfeng Tang , Gangjian Tan
Energy & Environmental Materials ›› 2024, Vol. 7 ›› Issue (2) : 12535
Engineering Thermoelectric Performance of α-GeTe by Ferroelectric Distortion
The rhombohedral α-GeTe can be approximated as a slightly distorted rock-salt structure along its [1 1 1] direction and possesses superb thermoelectric performance. However, the role of such a ferroelectric-like structural distortion on its transport properties remains unclear. Herein, we performed a systematic study on the crystal structure and electronic band structure evolutions of Ge1-xSnxTe alloys where the degree of ferroelectric distortion is continuously tuned. It is revealed that the band gap is maximized while multiple valence bands are converged at x = 0.6, where the ferroelectric distortion is the least but still works. Once undistorted, the band gap is considerably reduced, and the valence bands are largely separated again. Moreover, near the ferro-to-paraelectric phase transition Curie temperature, the lattice thermal conductivity reaches its minima because of significant lattice softening enabled by ferroelectric instability. We predict a peak ZT value of 2.6 at 673 K in α-GeTe by use of proper dopants which are powerful in suppressing the excess hole concentrations but meanwhile exert little influence on the ferroelectric distortion.
electronic band structures / ferroelectric distortion / lattice softening / thermoelectric / α-GeTe
| [1] |
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| [2] |
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| [3] |
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| [4] |
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| [5] |
|
| [6] |
|
| [7] |
|
| [8] |
|
| [9] |
|
| [10] |
|
| [11] |
|
| [12] |
|
| [13] |
|
| [14] |
|
| [15] |
|
| [16] |
|
| [17] |
|
| [18] |
|
| [19] |
|
| [20] |
|
| [21] |
|
| [22] |
|
| [23] |
|
| [24] |
|
| [25] |
|
| [26] |
|
| [27] |
|
| [28] |
|
| [29] |
|
| [30] |
|
| [31] |
|
| [32] |
|
| [33] |
|
| [34] |
|
| [35] |
|
| [36] |
|
| [37] |
|
| [38] |
|
| [39] |
|
| [40] |
|
| [41] |
|
| [42] |
|
| [43] |
|
| [44] |
|
| [45] |
|
| [46] |
|
| [47] |
|
| [48] |
|
| [49] |
|
| [50] |
|
| [51] |
|
| [52] |
|
| [53] |
|
| [54] |
|
| [55] |
|
| [56] |
|
| [57] |
|
| [58] |
|
| [59] |
|
| [60] |
|
| [61] |
|
| [62] |
|
| [63] |
|
| [64] |
|
| [65] |
|
| [66] |
|
| [67] |
|
| [68] |
|
| [69] |
|
| [70] |
|
| [71] |
|
| [72] |
|
| [73] |
|
| [74] |
|
| [75] |
|
| [76] |
|
| [77] |
|
| [78] |
|
| [79] |
|
| [80] |
|
| [81] |
|
2022 The Authors. Energy & Environmental Materials published by John Wiley & Sons Australia, Ltd on behalf of Zhengzhou University.
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