权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

MoWSe_Spin and pseudospin properties of energetically controllable dark and bright excitons in tailored Mo1-xWxSe2 alloys

MoWSe_定制 Mo1-xWxSe2 合金中能量可控暗激子和亮激子的自旋和赝自旋特性

基本信息

批准号：
382264508
负责人：
Dr. Jörg Debus
金额：
--
依托单位：
Lehrstuhl für Experimentelle Physik II
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/382264508?language=en
关键词：
MoWSe_Spin pseudospin properties energetically controllable

项目摘要

Two-dimensional transition metal dichalcogenides, whose layered structure allows for unusually strongly bound excitons existing even at room temperature, possess unique spin and valley pseudospin features that may give rise to highly exciting and novel physics for the nanophotonics as well as spin-based nanoelectronics. In order to exploit the full potential of this new material system and to allow one to tailor the functional and structural properties of these nanomaterials, key open questions regarding the excitons in their monolayers have to be answered.For that purpose, we focus on the interaction between optically bright and dark K-valley excitons in novel Mo1-xWxSe2 alloys. The composition dependence of these mechanically exfoliated alloys shall allow us to tune the energies of the A- and B-exciton spin states, also leading to a dark- and bright-exciton mixing, in a wide range. Using the Mo1-xWxSe2 structures with tunable conduction- and valence-band levels, we expect to provide novel and thorough insights into the spin and valley pseudospin properties and dynamics, which shall be studied with regard to the tunable exciton and carrier exchange interactions and spin-orbit coupling as well as to the interaction of the excitons with the surrounding bath. The latter shall include not only nuclear spins and phonons, but also defects, substrate materials and the monolayer geometry. Optically detected magnetic resonance techniques combined with resonant and polarized laser excitation and micrometer spatial resolution shall allow for a magnetic resonance imaging of the spin-based exciton properties, thus making a step toward spin-based quantum information devices and sensor technologies. Besides the composition-dependent controllability of the dark and bright exciton energies, we will apply uni- and biaxial strain to the substrate material for fine-tuning the spin state energies, manipulating the spin-orbit coupling of the electrons and particularly holes and changing symmetry conditions. A comparative study of the K- and Gamma-valley excitons shall furthermore enhance the understanding of spin and many-carrier physics, by exploiting high-energy laser excitation with variable power, in the tailored Mo1-xWxSe2 structures.

二维过渡金属二硫族化合物，其层状结构允许在室温下存在异常强烈的束缚激子，具有独特的自旋和谷伪自旋特征，可能会为纳米光子学和基于自旋的纳米电子学带来高度令人兴奋和新颖的物理学。为了充分利用这种新材料系统的潜力，并允许人们定制这些纳米材料的功能和结构特性，必须回答有关其单层中的激子的关键开放性问题。为此，我们重点研究了新型Mo1-xWxSe2合金中光学亮和暗k谷激子之间的相互作用。这些机械剥离合金的成分依赖性将使我们能够调整A和b激子自旋态的能量，也导致暗激子和亮激子在大范围内混合。利用具有可调导带和价带能级的Mo1-xWxSe2结构，我们期望对自旋和谷伪自旋性质和动力学提供新颖而深入的见解，这些性质和动力学将在可调激子与载流子交换相互作用和自旋-轨道耦合以及激子与周围镀液的相互作用方面进行研究。后者不仅包括核自旋和声子，还包括缺陷、衬底材料和单层几何结构。光学探测磁共振技术结合共振和偏振激光激发和微米空间分辨率，将允许对基于自旋的激子性质进行磁共振成像，从而向基于自旋的量子信息器件和传感器技术迈出了一步。除了暗激子和亮激子能量的成分依赖可控性外，我们还将对衬底材料施加单轴和双轴应变，以微调自旋态能量，操纵电子（特别是空穴）的自旋轨道耦合以及改变对称条件。通过在定制的Mo1-xWxSe2结构中利用可变功率的高能激光激发，对K-和γ -谷激子的比较研究将进一步增强对自旋和多载流子物理的理解。