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arXiv 1709.01765cond-mat.mes-hall
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扭曲双层黑磷中的栅诱导单层行为

Gate induced monolayer behavior in twisted bilayer black phosphorus

Cem Sevik, John R. Wallbank, Oguz Gulseren, Francois M. Peeters, Deniz Cakır

摘要:

黑磷的光学和电子性质强烈地依赖于层的数量和堆叠的类型。利用密度泛函理论框架下的第一性原理计算,研究了层间扭曲角为90 $^\circ$的双层黑磷的电子性质.这些计算与一个简单的$\vec{k}\cdot\vec{p}$模型,它是能够捕获的低能量的功能,是有效的任意扭转角。发现90 $^\circ$扭曲双层黑磷的电子光谱与单层相比是x-y各向同性的。然而,x-y各向异性和部分返回到单层样行为,特别是在价带中,可以由外部面外电场诱导。此外,优选的空穴有效质量可以简单地通过改变所施加的电场的方向而旋转90 $^\circ$。特别地,+0.4(-0.4)V/V的面外电场导致空穴有效质量沿y(x)轴增加60%,并将$m^*_{y}/m^*_{x}$($m^*_{x}/m^*_{y}$)比提高多达40倍。我们的DFT和$\vec{k}\cdot\vec{p}$模拟清楚地表明,结合适当的栅极电压的扭曲角是一种新的方式来调整双层磷的电子和光学性质,它给了我们一个新的自由度,工程黑磷基器件的性能。

英文摘要:

Optical and electronic properties of black phosphorus strongly depend on the number of layers and type of stacking. Using first-principles calculations within the framework of density functional theory, we investigate the electronic properties of bilayer black phosphorus with an interlayer twist angle of 90$^\circ$. These calculations are complemented with a simple $\vec{k}\cdot\vec{p}$ model which is able to capture most of the low energy features and is valid for arbitrary twist angles. The electronic spectrum of 90$^\circ$ twisted bilayer black phosphorus is found to be x-y isotropic in contrast to the monolayer. However x-y anisotropy, and a partial return to monolayer-like behavior, particularly in the valence band, can be induced by an external out-of-plane electric field. Moreover, the preferred hole effective mass can be rotated by 90$^\circ$ simply by changing the direction of the applied electric field. In particular, a +0.4 (-0.4) V/Å out-of-plane electric field results in a $\sim$60\% increase in the hole effective mass along the y (x) axis and enhances the $m^*_{y}/m^*_{x}$ ($m^*_{x}/m^*_{y}$) ratio as much as by a factor of 40. Our DFT and $\vec{k}\cdot\vec{p}$ simulations clearly indicate that the twist angle in combination with an appropriate gate voltage is a novel way to tune the electronic and optical properties of bilayer phosphorus and it gives us a new degree of freedom to engineer the properties of black phosphorus based devices.

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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