论文标题
通过CR掺杂调节晶格醇酯的晶格导热率
Tuning the lattice thermal conductivity in Bismuth Telluride through Cr-doping
论文作者
论文摘要
降低热电材料的导热率始终是其潜在应用的先决条件。使用第一原则计算，我们检查了磁尿中晶格热传输的磁性变化。磁矩的来源，掺杂的系统中的Cr，弱磁化为协调的TE原子，使后者的声子柔软于纯化合物中的声子。尽管过渡金属掺杂剂不直接参与热传导过程，但它们引起的非谐调性在降低晶格导热率方面有利。 $（bi_ {0.67} cr_ {0.33}）_ 2te_3 $中的大型非harmonicity将平面内温度晶格导热率降低$ \ sim 79 \％$。严格来说，导热率不会随着掺杂浓度而单调的变化。即使对于任何特定的掺杂水平，对于与系统的内部能量有关的不同构型，导热率也不同。我们发现，0.03 $ eV $的内部能量差异将使室温晶格的平面内电导率降低至少60美元$ \％$ \％$ \％$ \％$ $ \％$。
Decreasing thermal conductivity of a thermoelectric material is always a prerequisite for its potential application. Using first-principle calculations, we examine the magnetism induced change in lattice thermal transport in bismuth telluride. The source of magnetic moment, Cr in the doped system, weakly magnetizes the coordinated Te atoms to make the latter's phonon softer than that in the pure compound. Though the transition metal dopants do not participate directly in the heat conduction process, the anharmonicity induced by them favor in reducing the lattice thermal conductivity. Large anharmonicity in $(Bi_{0.67}Cr_{0.33})_2Te_3$ reduces the in-plane room temperature lattice thermal conductivity by $\sim 79\%$. The thermal conductivity, strictly, does not vary monotonically with doping concentration. Even, for any particular doping level, the thermal conductivity is different for different configurations which is related to the internal energy of the system. We found that the internal energy variance of 0.03 $eV$ would reduce the in-plane thermal conductivity of the room temperature lattice by at least 60$\%$ for 50$\%$ doping.
