Gajaria Trupti K, Dabhi Shweta D, Jha Prafulla K
Department of Physics, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara, 390002, Gujarat, India.
P. D. Patel Institute of Applied Science, Charotar University of Science and Technology, CHARUSAT campus, Changa, 388421, Gujarat, India.
Sci Rep. 2019 Apr 10;9(1):5884. doi: 10.1038/s41598-019-41982-9.
The state-of-the-art Density Functional Theory (DFT) is utilized to investigate the structural, electronic, vibrational, thermal and thermoelectric properties of gallium pnictides GaX (X = P, As, Sb) in cubic zincblende (ZB) and hexagonal wurtzite (WZ) phases. The lattice parameters, bulk modulus, energy band nature and bandgap values, phonon, thermal and thermoelectric properties are revisited for ZB phase while for WZ phase they are predictive. Our results agree reasonably well with the experimental and theoretical data wherever they are available. The phonon dispersion curves are computed to validate the dynamic stability of these two polytypes and for further investigating the thermal and thermoelectric properties. Our computed thermoelectric figure of merit ZT gives consistent results with highest observed magnitude of 0.72 and 0.56 for GaSb compound in ZB and WZ phases respectively. The first time calculated temperature variation of lattice thermal conductivity for WZ phase shows lower value than ZB phase and hence an important factor to enhance the figure of merit of considered gallium pnictides in WZ phase. Present results validate the importance of GaX in high temperature thermoelectric applications as the figure of merit ZT shows enhancement with significant reduction in thermal conductivity at higher temperature values.
利用最先进的密度泛函理论（DFT）研究立方闪锌矿（ZB）相和六方纤锌矿（WZ）相的镓磷化物GaX（X = P、As、Sb）的结构、电子、振动、热和热电性质。重新审视了ZB相的晶格参数、体模量、能带性质和带隙值、声子、热和热电性质，而对于WZ相，这些性质是预测性的。在有实验和理论数据的地方，我们的结果与它们相当吻合。计算声子色散曲线以验证这两种多晶型的动态稳定性，并进一步研究热和热电性质。我们计算的热电优值ZT给出了一致的结果，对于ZB相和WZ相的GaSb化合物，分别观察到最高值0.72和0.56。首次计算的WZ相晶格热导率随温度的变化显示其值低于ZB相，因此这是提高WZ相镓磷化物优值的一个重要因素。目前的结果证实了GaX在高温热电应用中的重要性，因为优值ZT在较高温度下显示出提高，同时热导率显著降低。
