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arXiv 1909.08503cond-mat.mtrl-sci
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$\mathrm{Ga_2O_3}$压电性能的第一性原理研究

Piezoelectric properties of $\mathrm{Ga_2O_3}$: a first-principle study

San-Dong Guo, Hui-Min Du

摘要:

这类化合物具有压电性,而压电性的产生需要打破反转对称性,才能成为半导体。对于$\mathrm{Ga_2O_3}$,常见五相的正交情况($ε$ - $\mathrm{Ga_2O_3}$)破坏了反转对称性。本文采用密度泛函微扰理论(DFPT)计算了$ε$ - $\mathrm{Ga_2O_3}$的压电张量.为了证实$ε$ - $\mathrm{Ga_2O_3}$的半导体性质,用广义梯度近似(GGA)和Tran和Blaha的修正Becke和Johnson(mBJ)交换势研究了它的电子结构.用mBJ方法预测的带隙值为4.66 eV,以及导带最小值(CBM)处电子的有效质量张量[约0.24 $m_0$ ]。mBJ间隙非常接近可用的实验值。通过离散傅里叶变换得到弹性张量$C_{ij}$和压电应力张量$e_{ij}$,再由$C_{ij}$和$e_{ij}$计算压电应变张量$d_{ij}$。在此过程中,估算了$ε$ - $\mathrm{Ga_2O_3}$的平均力学性能,如体积模量、剪切模量、杨氏模量等,计算得到的$d_{ij}$与常用的压电材料如$α$ -石英、ZnO、AlN和GAN相当甚至更高。

英文摘要:

The compounds exhibit piezoelectricity, which demands to break inversion symmetry, and then to be a semiconductor. For $\mathrm{Ga_2O_3}$, the orthorhombic case ($ε$-$\mathrm{Ga_2O_3}$) of common five phases breaks inversion symmetry. Here, the piezoelectric tensor of $ε$-$\mathrm{Ga_2O_3}$ is reported by using density functional perturbation theory (DFPT). To confirm semiconducting properties of $ε$-$\mathrm{Ga_2O_3}$, its electronic structures are studied by using generalized gradient approximation (GGA) and Tran and Blaha's modified Becke and Johnson (mBJ) exchange potential. The gap value of 4.66 eV is predicted with mBJ method, along with the the effective mass tensor for electrons at the conduction band minimum (CBM) [about 0.24 $m_0$]. The mBJ gap is very close to the available experimental value. The elastic tensor $C_{ij}$ and piezoelectric stress tensor $e_{ij}$ are attained by DFPT, and then piezoelectric strain tensor $d_{ij}$ are calculated from $C_{ij}$ and $e_{ij}$. In this process, average mechanical properties of $ε$-$\mathrm{Ga_2O_3}$ are estimated, such as bulk modulus, Shear modulus, Young's modulus and so on. The calculated $d_{ij}$ are comparable and even higher than commonly used piezoelectric materials such as $α$-quartz, ZnO, AlN and GaN.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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