β型锑烯热电输运性质的第一性原理研究

First-Principles Study of Thermoelectric Transport Properties of β-Antimonene

利用第一性原理与半经典玻尔兹曼方程,计算并分析β型锑烯的声子色散、声子群速度、声子弛豫时间、晶格热导率及不同温度下的塞贝克系数、电导率和电子热导率随化学势的变化;结果表明：β型锑烯由于非平面六角结构,三支声学声子在Γ点附近均呈线性变化;声学声子对整个晶格热导率的贡献高达96.68%,而光学声子仅仅占到3.32%;由于较大的声光带隙（a-o gap）导致LA支在声子群速度和弛豫时间中占据主导地位,从而增大了LA支声子对整个热导的贡献;热电优值随温度的升高而增大,在费米面附近其绝对值最大可达0.275.

First-principles and semiclassical Boltzmann transport formalism are employed to investigate thermoelectric properties of β-antimonene. We obtain phonon dispersion,phonon group velocity,phonon relaxation time,lattice thermal conductivity and Seebeck coefficient,electrical conductivity and electron thermal conductivity as functions of chemical potential of β-antimonene. It indicates that longitudinal acoustic（ LA）,transverse acoustic（ TA）,and z-direction acoustic（ ZA） branches of β-antimonene are linear near Γpoint due to its buckling structure. Acoustic phonon contribution to whole lattice thermal conductivity is as high as 96. 68%,and optical phonon accounts for 3. 32% only. A large a-o gap leads to LA be dominant in group velocity and relaxation time,and thus increasing LA phonon contribution to whole thermal conductivity. In addition,merit ZT increases with temperature,and reaching a maximum of 0. 275 at 700 K near Fermi level.