Intrinsically minimal thermal conductivity in cubic I-V-VI2 semiconductors
Intrinsically minimal thermal conductivity in cubic I-V-VI2 semiconductors
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DOI：
10.1103/physrevlett.101.035901
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发表时间：
2008-07-18
影响因子：
8.6
通讯作者：
Heremans, J. P.
中科院分区：
文献类型：
--
作者：
Morelli, D. T.;Jovovic, V.;Heremans, J. P.
报道了高质量立方I-V-VI2半导体晶体AgSbTe2和AgBiSe2的热导率测量结果。在约0.70W/mK时，热导率在80~300K之间与温度无关。热传导是由晶格项决定的，我们发现晶格项受到umclapp和正常的声子-声子散射过程的限制，其值对应于可能的最小值，其中声子平均自由程等于原子间距离。立方I-V-VI2半导体的最小热导率是由于晶格振动光谱的极端非谐性导致了高的Gruneisen参数和强烈的声子-声子相互作用。因此，这类化合物的成员最有希望用于热电应用，特别是作为p型材料。
We report measurements of the thermal conductivity of high-quality crystals of the cubic I-V-VI2 semiconductors AgSbTe2 and AgBiSe2. The thermal conductivity is temperature independent from 80 to 300 K at a value of approximately 0.70 W/mK. Heat conduction is dominated by the lattice term, which we show is limited by umklapp and normal phonon-phonon scattering processes to a value that corresponds to the minimum possible, where the phonon mean free path equals the interatomic distance. Minimum thermal conductivity in cubic I-V-VI2 semiconductors is due to an extreme anharmonicity of the lattice vibrational spectrum that gives rise to a high Gruneisen parameter and strong phonon-phonon interactions. Members of this family of compounds are therefore most promising for thermoelectric applications, particularly as p-type materials.