Straintronics with van der Waals Ferroelectrics

应变电子学与范德华铁电体

• 批准号: 535379969
• 负责人: Dr. Emeline Nysten
• 金额: --
• 依托单位: Physikalisches Institut
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/535379969?language=en
• 关键词: Straintronics; van; der; Waals; Ferroelectrics

Ferroelectricity is a fundamental phenomenon in solid-state physics and ferroelectric devices are indispensable in many applications and devices. When stacking two-dimensional semiconductors in van der Waals (vdW) homo- and heterostructures, ferroelectricity emerges at the interface for well-defined twist angles between the stacked planes. This interfacial ferroelectricity is caused by the breaking of the inversion symmetry between the two layers which leads an interlayer charge transfer. This transfer in turn creates a strong spontaneous out-of-plane electric dipole moment which manifests itself in ferroelectric domain patterns. The overarching goal of this project is to probe and manipulate interfacial ferroelectricity in semiconducting vdW structures employing a combination of static electric fields and dynamic strain. The dynamic strain is generated in the form of surface acoustic waves (SAWs) at frequencies up to a few gigahertz. In this project we will develop the simulation and nanofabrication technology of hybrid vdW-SAW devices. Using these devices, we pursue two main research tracks: 1) First, non-ferroelectric (H-stacked) gated vdW bilayer devices will be fabricated on LiNbO3 and LiTaO3 SAW-chips. In these vdW bilayers, intralayer (electron and hole in the same layer) and interlayer (electron and hole in different layers) excitons form, which can be elegantly controlled by a gate voltage which provides a global, quasi-static tuning parameter. The such programmed excitonic species are dynamically controlled in programmable acoustic potentials generated by superimposed SAW beams and read out optically using time- and position-resolved optical spectroscopy. 2) Second, we will fabricate ferroelectric (R-stacked) gated vdW bilayer devices on LiNbO3 and LiTaO3 SAW chips. These two substrates allow for the generation of dynamic normal and shear stress in the form of Rayleigh and shear horizontal (SH) SAWs. Ferroelectric polarization, domain walls and hysteresis will be controlled by dynamic normal and shear stress and detected by optical and electrical spectroscopy.

铁电性是固态物理学中的一种基本现象，在许多应用和设备中，铁电器的设备都是必不可少的。当将二维半导体堆叠在范德华（VDW）同型和异质结构中时，在堆叠平面之间定义明确的扭角处出现铁电性。这种界面的铁电性是由两层倒置对称性的破坏引起的，从而导致层间电荷转移。反过来，这种转移产生了强大的自发性脱极偶极矩，从而在铁电域模式中表现出来。该项目的总体目标是在半导体的VDW结构中探测和操纵界面的铁电性，该结构采用了静态电场和动态应变的组合。动态应变是以表面声波（SAW）形式产生的，以高达几吉赫兹的频率。在这个项目中，我们将开发混合VDW-SAW设备的仿真和纳米制作技术。使用这些设备，我们追求两个主要的研究轨道：1）首先将在Linbo3和Litao3 Saw-Chips上制造，首先是非弗洛（H-stacked）门控VDW双层设备。在这些VDW双层中，内层（同一层中的电子和孔）和中间层（不同层中的电子和孔）激子形式，可以通过提供全局的准静态调谐参数的栅极电压来优雅地控制。此类编程的激子物种在叠加的锯梁产生的可编程声势中动态控制，并使用时间和位置分辨的光谱光学读取。 2）第二，我们将在linbo3和litao3看到芯片上制造铁电（R堆放）封闭式VDW双层设备。这两个底物允许以雷利和剪切水平（SH）锯的形式产生动态正常和剪切应力。铁电偏振，结构壁和滞后将由动态正常和剪切应力控制，并通过光学光谱检测。