Confinement epitaxy beneath graphene stabilizes exotic material phases by restricting vertical growth and altering lateral diffusion, conditions unattainable on bare substrates. However, achieving long-range interfacial order while maintaining high-quality graphene remains a significant challenge. Here, we demonstrate the synthesis of large-area quasi-free-standing monolayer graphene (QFMLG) via the intercalation of a two-dimensional (2D) Sn. While the triangular Sn(1x1) interface exhibits a robust metallic band structure, the decoupled QFMLG maintains charge neutrality, confirmed by photoemission spectroscopy. Using high-resolution Raman spectroscopy and microscopy, we distinguish between direct intercalation and diffusion-driven expansion, identifying the latter as the critical pathway to superior QFMLG crystalline quality. Temperature-dependent analysis reveals dynamical structural coupling between the decoupled QFMLG and the Sn interface, providing a novel degree of freedom for strain engineering. Beyond uncovering the diffusion-driven mechanism, this work establishes metal intercalation as an effective strategy for tailoring durable graphene-metal heterostructures with tunable properties for next-generation quantum materials platforms.
Momentum microscopy of Pb-intercalated graphene on SiC: charge neutrality and electronic structure of interfacial Pb
插层是用于定制外延石墨烯的电子结构的已建立的技术。此外,由于界面量子限制,它能够合成与其体版本相比具有独特物理特性的元件的不稳定的二维(2D)层。在这项工作中,我们提出了均匀的Pb插层准独立单层石墨烯在SiC上,这证明是基本上是电荷中性的,具有前所未有的$p$型载流子密度,只有$(5.5\pm2.5)\times10^9$ cm $^{-2}$。通过动量显微镜探测整个第一表面布里渊区的低能电子结构,我们清楚地辨别出与界面处的金属2D-Pb相关的附加带。低能电子衍射进一步揭示了相对于石墨烯的$10\times10$莫尔超周期性,其对应物不能在可用的能带结构数据中直接识别。我们的实验证明了重元素超导体的二维层间限制和相关的能带结构形成,为石墨烯/SiC界面处的强自旋轨道耦合效应甚至二维超导性铺平了道路。
Surface charge-transfer doping a quantum-confined silver monolayer beneath epitaxial graphene
最近,石墨烯/SiC界面已经成为一个通用的平台,否则不稳定的,单元素,二维(2D)层通过嵌入外延。它们内部覆盖了一个带有顶部石墨烯的范德华异质结构,构成了一类新的量子材料,与它们的母体大块晶体相比具有惊人的特性。嵌入银提出了一个典型的例子,其中2D量子限制和反转对称性破缺需要金属到半导体的转变。然而,很少有人知道相关的未被占领的国家,和控制费米能级的位置跨越带隙将是可取的。在这里,我们通过原位钾沉积对石墨烯/2D-Ag/SiC异质叠层进行n型掺杂,并通过基于同步加速器的角度分辨光电子能谱学探测其能带结构。虽然在$10^{14}$ cm $^{-2}$数量级上的诱导载流子密度还不足以达到银导带的起始,但是石墨烯的能带排列相对于刚性移动的Ag价带和衬底芯能级而改变。我们进一步证明了一个有序的钾吸附层($2\times 2$相对于石墨烯)与自由电子的分散,通过增强金属化的异质叠层抑制等离子体准粒子在石墨烯。我们的研究结果建立了表面电荷转移掺杂作为一种有效的处理,以修改能带排列和电子性质的范德华异质结构组装从石墨烯和一种新型的单层量子材料。
Orbital Hybridization-Induced Ising-Type Superconductivity in a Confined Gallium Layer
The Pennsylvania State University(宾夕法尼亚州立大学);Shanghai Jiao Tong University(上海交通大学);University of Oxford(牛津大学);Zhejiang University(浙江大学);Diamond Light Source(钻石光源研究所);University of North Texas(北德克萨斯大学)
Above-room-temperature ferromagnetism in large-area epitaxial Fe3GaTe2/graphene van der Waals heterostructures
Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V.(柏林莱布尼茨固体电子学保罗·德鲁德研究所);Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research e.V.(德累斯顿-罗森多夫亥姆霍兹中心离子束物理与材料研究所);QZabre AG(QZabre股份公司);Helmholtz Zentrum Berlin for Materialien und Energie(柏林亥姆霍兹材料与能源中心)