Sreeparvathy P C, Kanchana V
Department of Physics, Indian Institute of Technology Hyderabad, Kandi, 502 285, Sangareddy, Telangana, India.
J Phys Condens Matter. 2018 Jul 25;30(29):295501. doi: 10.1088/1361-648X/aaca6a. Epub 2018 Jun 5.
We report the electronic structure and thermoelectric (TE) properties of OsX (X: S, Se, Te), and find a giant value of thermopower of magnitude 600 μV K-800 μV K for a wide temperature range of 100 K-500 K for hole doping (at 10 cm), which is higher than the value found for well established TE materials. The optimized structural parameters are in good agreement with available experimental reports. The mechanical stability of all the compounds are confirmed from the computed elastic constants. The band gap of the investigated compounds is examined by several exchange correlation functionals, and TB-mBJ with modified parameters is found to be the best. The heavy valence bands stimulate the thermopower value for hole doping and light conduction bands intensifies the electrical conductivity values for electron doping, enabling both 'n' and 'p' type doping favourable for TE applications at higher concentrations (10 cm), which brings out the device application. Our results unveil the possibility of TE applications for all the examined compounds for a wide temperature range (100 K-500 K), and OsS specifically is quite alternative with the performing temperature ranging from 100 K-900 K.
我们报告了OsX（X：S、Se、Te）的电子结构和热电（TE）性质，发现在空穴掺杂（浓度为10 cm）时，在100 K至500 K的宽温度范围内，热功率值高达600 μV K - 800 μV K，这高于已成熟的TE材料的值。优化后的结构参数与现有实验报告吻合良好。通过计算弹性常数确认了所有化合物的力学稳定性。采用多种交换关联泛函研究了所研究化合物的带隙，发现具有修正参数的TB - mBJ是最佳的。重价带促进了空穴掺杂时的热功率值，而轻导带增强了电子掺杂时的电导率值，使得在较高浓度（10 cm）下“n”型和“p”型掺杂都有利于TE应用，从而实现了器件应用。我们的结果揭示了在宽温度范围（100 K - 500 K）内所有被研究化合物用于TE应用的可能性，特别是OsS在100 K - 900 K的工作温度范围内颇具潜力。
