Carrier distribution in multi-band materials and its effect on thermoelectric properties
Band convergence is one of the most interesting topics in recent studies of thermoelectrics. However, its effect on thermoelectric properties is only simply stated as improving band degeneracy. In this paper, the enhanced thermoelectric performance due to band convergence is clarified from the viewp...
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| Format: | Article |
| Language: | English |
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Elsevier
2016-06-01
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| Series: | Journal of Materiomics |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2352847816300028 |
| _version_ | 1797813899202920448 |
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| author | Jun Mao Weishu Liu Zhifeng Ren |
| author_facet | Jun Mao Weishu Liu Zhifeng Ren |
| author_sort | Jun Mao |
| collection | DOAJ |
| description | Band convergence is one of the most interesting topics in recent studies of thermoelectrics. However, its effect on thermoelectric properties is only simply stated as improving band degeneracy. In this paper, the enhanced thermoelectric performance due to band convergence is clarified from the viewpoint of distribution of carriers in the electronic bands. The n-type Mg2Sn0.75Ge0.25 is used as a case study, and the effect of band offset E on its thermoelectric properties is investigated based on the three-band model, i.e., one light conduction band, one heavy conduction band, and one valence band. The results show that E has a decisive effect on controlling the distribution of carriers in the two conduction bands, thus affecting the thermoelectric properties. Since the optimal carrier concentration nopt is related to the density of state effective mass m∗ at a given temperature, an appropriate distribution of carriers should be a higher carrier concentration in the heavy band (with larger m∗) and a lower carrier concentration in the light band (with smaller m∗). In order to achieve a proper distribution of carriers, E should be as small as possible at any temperature, which explains the reason why band convergence could lead to the enhanced thermoelectric performance. |
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| format | Article |
| id | doaj.art-cacccb2cfb124938b3ac8a6fcc73416d |
| institution | Directory Open Access Journal |
| issn | 2352-8478 |
| language | English |
| last_indexed | 2024-03-13T07:59:32Z |
| publishDate | 2016-06-01 |
| publisher | Elsevier |
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| series | Journal of Materiomics |
| spelling | doaj.art-cacccb2cfb124938b3ac8a6fcc73416d2023-06-02T00:08:09ZengElsevierJournal of Materiomics2352-84782016-06-012220321110.1016/j.jmat.2016.03.001Carrier distribution in multi-band materials and its effect on thermoelectric propertiesJun Mao0Weishu Liu1Zhifeng Ren2Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, TX 77204, USADepartment of Physics and Texas Center for Superconductivity, University of Houston, Houston, TX 77204, USADepartment of Physics and Texas Center for Superconductivity, University of Houston, Houston, TX 77204, USABand convergence is one of the most interesting topics in recent studies of thermoelectrics. However, its effect on thermoelectric properties is only simply stated as improving band degeneracy. In this paper, the enhanced thermoelectric performance due to band convergence is clarified from the viewpoint of distribution of carriers in the electronic bands. The n-type Mg2Sn0.75Ge0.25 is used as a case study, and the effect of band offset E on its thermoelectric properties is investigated based on the three-band model, i.e., one light conduction band, one heavy conduction band, and one valence band. The results show that E has a decisive effect on controlling the distribution of carriers in the two conduction bands, thus affecting the thermoelectric properties. Since the optimal carrier concentration nopt is related to the density of state effective mass m∗ at a given temperature, an appropriate distribution of carriers should be a higher carrier concentration in the heavy band (with larger m∗) and a lower carrier concentration in the light band (with smaller m∗). In order to achieve a proper distribution of carriers, E should be as small as possible at any temperature, which explains the reason why band convergence could lead to the enhanced thermoelectric performance.http://www.sciencedirect.com/science/article/pii/S2352847816300028ThermoelectricBand convergenceThree-band modelDistribution of carriersOptimal carrier concentration |
| spellingShingle | Jun Mao Weishu Liu Zhifeng Ren Carrier distribution in multi-band materials and its effect on thermoelectric properties Journal of Materiomics Thermoelectric Band convergence Three-band model Distribution of carriers Optimal carrier concentration |
| title | Carrier distribution in multi-band materials and its effect on thermoelectric properties |
| title_full | Carrier distribution in multi-band materials and its effect on thermoelectric properties |
| title_fullStr | Carrier distribution in multi-band materials and its effect on thermoelectric properties |
| title_full_unstemmed | Carrier distribution in multi-band materials and its effect on thermoelectric properties |
| title_short | Carrier distribution in multi-band materials and its effect on thermoelectric properties |
| title_sort | carrier distribution in multi band materials and its effect on thermoelectric properties |
| topic | Thermoelectric Band convergence Three-band model Distribution of carriers Optimal carrier concentration |
| url | http://www.sciencedirect.com/science/article/pii/S2352847816300028 |
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