Structural, electronic, and polarization properties of YN and LaN,Physical Review Materials

当前位置： X-MOL 学术 › Phys. Rev. Materials › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Structural, electronic, and polarization properties of YN and LaN
Physical Review Materials ( IF 3.1 ) Pub Date : 2021-09-07 , DOI: 10.1103/physrevmaterials.5.094602
A. J. E. Rowberg ₁ , S. Mu ₁ , M. W. Swift ₂ , C. G. Van de Walle ₁

Affiliation

ScN has attracted great attention for its electronic properties and its ability to enhance polarization of AlN; however, its sister compounds, YN and LaN, remain much less studied. Here, we use first-principles calculations to evaluate YN and LaN in their cubic and hexagonal phases. Rocksalt YN and LaN are semiconductors, although we show that LaN differs from ScN and YN in having a direct band gap, which we attribute to its weaker

p − p

coupling. Both have low electron effective masses. In addition to their rocksalt structures, we evaluate the layered hexagonal and wurtzite phases of YN and LaN. For YN, the wurtzite phase cannot be stabilized, and hexagonal YN is higher in energy than rocksalt YN. In contrast, for LaN, the wurtzite phase is favored, and it is comparable in energy to rocksalt LaN. Wurtzite LaN has a polarization of

0.608 C / m^{2}

(referenced to the centrosymmetric layered hexagonal phase), and a high piezoelectric coefficient

e_{33} = 1.78 C / m^{2}

. Interestingly, we find that the polarization of wurtzite LaN may be reversible; we find a relatively small switching barrier of 0.06 eV per formula unit, offering the potential for its use as a ferroelectric. Since wurtzite LaN is closely lattice matched to InP, we investigate a heterostructure between (0001) wurtzite LaN and (111) zinc-blende InP, and find the polarization discontinuity would yield a bound charge of

1.3 \times 10^{14} e / {cm}^{2}

, offering the potential for novel electronic applications such as tunnel junctions. Our results compare and contrast ScN, YN, and LaN, and highlight the potential of these materials for adoption in electronic and ferroelectric devices.

中文翻译：

YN 和 LaN 的结构、电子和极化特性

ScN因其电子特性和增强AlN极化的能力而备受关注；然而，其姊妹化合物 YN 和 LaN 的研究仍然很少。在这里，我们使用第一性原理计算来评估 YN 和 LaN 的立方相和六方相。岩盐 YN 和 LaN 是半导体，尽管我们表明 LaN 与 ScN 和 YN 的不同之处在于具有直接带隙，我们将其归因于其较弱的

磷 - 磷

耦合。两者都具有低电子有效质量。除了它们的岩盐结构外，我们还评估了 YN 和 LaN 的层状六方相和纤锌矿相。对于YN，纤锌矿相不能稳定，六方YN的能量高于岩盐YN。相比之下，对于 LaN，纤锌矿相是有利的，它的能量与岩盐 LaN 相当。纤锌矿 LaN 的极化为

0.608 C / 米^{2}

（参考中心对称层状六方相）和高压电系数

{电子}_{33} = 1.78 C / 米^{2}

. 有趣的是，我们发现纤锌矿LaN 的极化可能是可逆的；我们发现每个公式单位的开关势垒相对较小，为 0.06 eV，提供了将其用作铁电体的潜力。由于纤锌矿 LaN 与 InP 晶格匹配紧密，我们研究了 (0001) 纤锌矿 LaN 和 (111) 闪锌矿 InP 之间的异质结构，发现极化不连续会产生束缚电荷