Electrically controlled ferromagnetism in 2-dimensional semiconductors

二维半导体中的电控铁磁性

• 批准号: 437096397
• 负责人: Privatdozent Dr. Michael Martins
• 金额: --
• 依托单位: Laboratoire de Physique de Solides - UMR 8502
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/437096397?language=en
• 关键词: Electrically; controlled; ferromagnetism; dimensional; semiconductors

The DIMAG project is dedicated to establishing a new type of 2D magnetic materials, which not only exhibits a fundamentally new type of ferromagnetic behavior, but also has optimal characteristics for spintronics applications. This 36-month project, brings together 5 academic laboratories: the Laboratory for Semiconductor Physics (KU Leuven, Belgium), the Institute for Nuclear and Radiation Physics (KU Leuven, Belgium), the Physics Department of the Hamburg University (Germany), the Laboratoire de Physique des Solides (CNRS, France), and Laboratory of Quantum Optics of the University of Nova Gorica (Slovenia). Each group brings highly specialized expertise, and advanced experimental and density functional theory methods that are key to achieving the goals of DIMAG, which in turn are beyond the state of the art. The general goal of DIMAG is to induce and study Stoner-type ferromagnetism in 2D semiconductors exhibiting a Van Hove singularity in the density of states (DOS), as predicted for GaSe, InSe, and SnO. First we will develop the synthesis of high-quality 2D materials with a controlled number of layers, by exfoliation from commercially available single crystals, as well as by molecular beam epitaxy. We will optimize the number of layers in order to maximize the DOS at the Van Hove singularity, as a compromise between low number of layers and high layer quality. In parallel, we will develop the control of the Fermi level in the vicinity of the Van Hove singularity (by acceptor doping and electrical gating), which is predicted to result in a Stoner instability and induce a ferromagnetic state. We will study these effects in detail: scanning tunnelling microscopy and spectroscopy to probe structural, electronic and magnetic properties at the atomic scale; angle resolved photoemission spectroscopy and inverse photoemission spectroscopy (static and time-resolved) to fully characterize the electronic structure below and above the Fermi level; X-ray magnetic circular dichroism and magneto-optical Kerr effect to establish the intrinsic origin of the ferromagnetic behavior. Based on this detailed understanding, we will optimize the materials synthesis, aiming to: (i) increase the ordering temperature and the carrier spin-polarization up to the highest achievable values; (ii) reversibly switch between ferromagnetic and non-ferromagnetic states with voltage bias. The DIMAG project directly addresses key goals of the Flagship work program, namely division 1 (Enabling Science and Materials), work packages 1 and 2 (WP1 - Enabling research; WP2 - Spintronics). In addition to its underlying fundamental nature, the project is highly application-oriented, as it aims to deliver new functionality that is device-compatible. Taking the Flagship’s WP1 and WP2 beyond graphene, into new 2D materials, DIMAG will have a tremendous impact, opening a broad new area of fundamental and applied research on new materials with device-compatible properties and functionality.

DIMAG 项目致力于建立一种新型的二维磁性材料，它不仅表现出一种全新的铁磁行为，而且还具有自旋电子学应用的最佳特性。这个为期 36 个月的项目汇集了 5 个学术实验室：半导体物理实验室（比利时鲁汶大学）、核与辐射物理研究所（比利时鲁汶大学）、汉堡大学物理系（德国）、固体物理实验室（法国国家科学研究中心）和新戈里察大学量子光学实验室 （斯洛文尼亚）。每个小组都带来高度专业化的专业知识以及先进的实验和密度泛函理论方法，这些方法是实现 DIMAG 目标的关键，而这些目标又超越了现有技术。 DIMAG 的总体目标是诱导和研究二维半导体中的斯通纳型铁磁性，该铁磁性在态密度 (DOS) 中表现出范霍夫奇点，正如对 GaSe、InSe 和 SnO 的预测一样。首先，我们将通过从市售单晶剥离以及分子束外延来开发具有受控层数的高质量二维材料的合成。我们将优化层数，以最大化 Van Hove 奇点处的 DOS，作为低层数和高层质量之间的折衷。与此同时，我们将开发对范霍夫奇点附近费米能级的控制（通过受主掺杂和电门控），预计这将导致斯托纳不稳定性并诱导铁磁态。我们将详细研究这些效应：扫描隧道显微镜和光谱学以探测原子尺度的结构、电子和磁性特性；角分辨光电子能谱和逆光电子能谱（静态和时间分辨），以全面表征费米能级以下和之上的电子结构； X 射线磁圆二色性和磁光克尔效应确定了铁磁行为的内在起源。基于这种详细的理解，我们将优化材料合成，旨在：（i）将有序温度和载流子自旋极化提高到可实现的最高值； (ii)利用电压偏置在铁磁和非铁磁状态之间可逆地切换。 DIMAG 项目直接解决旗舰工作计划的关键目标，即第 1 部分（实现科学和材料）、工作包 1 和 2（WP1 - 实现研究；WP2 - 自旋电子学）。除了其底层的基本性质之外，该项目还高度面向应用，因为它的目标是提供与设备兼容的新功能。 DIMAG 将旗舰版的 WP1 和 WP2 超越石墨烯，引入新型 2D 材料，将产生巨大影响，为具有设备兼容特性和功能的新材料开辟一个广阔的基础和应用研究新领域。