Pseudo-one dimensional (pseudo-1D) materials are a new-class of materials where atoms are arranged in chain like structures in two-dimensions (2D). Examples include recently discovered black phosphorus, ReS2 and ReSe2 from transition metal dichalcogenides, TiS3 and ZrS3 from transition metal trichalcogenides and most recently GaTe. The presence of structural anisotropy impacts their physical properties and leads to direction dependent light-matter interactions, dichroic optical responses, high mobility channels, and anisotropic thermal conduction. Despite the numerous reports on the vapor phase growth of isotropic TMDCs and post transition metal chalcogenides such as MoS2 and GaSe, the synthesis of pseudo-1D materials is particularly difficult due to the anisotropy in interfacial energy, which stabilizes dendritic growth rather than single crystalline growth with well-defined orientation. The growth of monoclinic GaTe has been demonstrated on flexible mica substrates with superior photodetecting performance. In this work, we demonstrate that pseudo-1D monoclinic GaTe layers can be synthesized on a variety of other substrates including GaAs (111), Si (111) and c-cut sapphire by physical vapor transport techniques. High resolution transmission electron microscopy (HRTEM) measurements, together with angle resolved micro-PL and micro-Raman techniques, provide for the very first time atomic scale resolution experiments on pseudo-1D structures in monoclinic GaTe and anisotropic properties. Interestingly, GaTe nanomaterials grown on sapphire exhibit highly efficient and narrow localized emission peaks below the band gap energy, which are found to be related to select types of line and point defects as evidenced by PL and Raman mapping scans. It makes the samples grown on sapphire more prominent than those grown on GaAs and Si, which demonstrate more regular properties.
Growth, stabilization and conversion of semi-metallic and semiconducting phases of MoTe2 monolayer by molecular-beam epitaxy
单层（ML）过渡金属二硫属化物以不同的相存在，例如六方（2 H）和畸变八面体或单斜（1 T '）相。不同的结构表现出截然不同的性质。例如，2 H MoTe 2 ML是直接带隙半导体，而1 T 'MoTe 2是半金属。有人提出，2 H和1 T 'MoTe 2之间的形成能相差很小，因此很有可能调整MoTe 2的结构，从而带来新的应用，如相变电子学。在这项工作中，我们报告的生长2 H和1 T 'MoTe 2 ML的分子束外延（MBE）。通过改变分子束外延的生长条件和退火，我们证明了外延MoTe 2结构域的可调谐性。我们目前的实验和理论证据表明，在分子束外延过程中，Te表面吸附在促进和稳定，否则亚稳1 T '-MoTe 2的重要作用。
High carrier mobility in single-crystal PtSe2 grown by molecular beam epitaxy on ZnO(0001)
PtSe 2作为一种高迁移率二维材料，在微电子学、光电探测和自旋电子学等领域有着广泛的应用前景。在绝缘衬底上生长具有晶片级均匀性的高质量PtSe 2是电子输运研究和器件实际应用的先决条件。在这里，我们报告的高度取向的少层PtSe 2 ZnO（0001）的分子束外延生长。用电子衍射、X射线衍射、原子力显微镜和透射电子显微镜对薄膜的晶体结构进行了表征。与生长在石墨烯、蓝宝石、云母、SiO2和Pt（111）上的PtSe 2层的比较表明，在绝缘衬底中，ZnO（0001）产生具有优异结构质量的膜。在ZnO/PtSe 2外延层上进行的霍尔测量显示出明显的半导体特性和高迁移率，室温下超过200 cm ~ 2 V ~（-1）s ~（-1），低温下高达447 cm ~ 2 V ~（-1）s ~（-1）。
Artificial Intelligence-Enabled Holistic Design of Catalysts Tailored for Semiconducting Carbon Nanotube Growth
Peking University（北京大学）；National Center for Nanoscience and Technology（国家纳米科学中心）；Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences（中国科学院上海微系统与信息技术研究所）；Suzhou Laboratory（苏州实验室）
New Materials, New Functionalities: Molecular Beam Epitaxy of Ultra-High Conductivity Oxides
Western Michigan University（西密歇根大学）；University of Delaware（特拉华大学）；Oak Ridge National Laboratory（橡树岭国家实验室）；Rutgers, The State University of New Jersey（新泽西州立罗格斯大学）
General and scalable vapor etching and transformation platform for two-dimensional materials
School of Materials Science and Engineering, Beihang University（北京航空航天大学材料科学与工程学院）；Linköping University（林雪平大学）；JiNan SCMXene Tech. Co., Ltd.（济南SCMXene科技有限公司）
Floquet engineering of titled and gapped Dirac materials
我们已经建立了一个严格的理论形式主义Floquet工程，或调查，并最终定制最关键的电子性质的四硫化钼（1 T $^\prime$ -MoS $_2$），通过施加外部高频修整场在非共振制度。最近的研究表明，单层掺杂的1 T $^\prime$ -MoS $_2$可以呈现出扭曲的四元结构，其具有可调谐的和带隙的自旋极化和谷极化的倾斜狄拉克能带结构。从电子学的角度来看，1 T $^\prime$ -MoS $_2$是技术上最有前途的纳米材料之一，也是已经著名的过渡金属二硫属元素家族的新代表。所得到的修饰态强烈依赖于所施加的照射的极化，并反映了未照射的材料的初始低能哈密顿量的全部复杂性。我们已经计算和分析了所获得的电子修饰状态的线性和圆形类型的极化的施加场集中在其对称性，各向异性，倾斜和带隙，以及拓扑签名。由于圆偏振的敷料场也被称为诱导到一个新的状态与破缺的时间反演对称性和非零陈数的过渡，这些拓扑非平凡的阶段和它们之间的过渡的组合可以揭示一些真正独特的和早期未知的现象。
From ferromagnetic semiconductor to anti-ferromagnetic metal in epitaxial Cr$_x$Te$_y$ monolayers
University of St Andrews（圣安德鲁斯大学）；STFC Central Laser Facility, Research Complex at Harwell（STFC中央激光设施，哈韦尔研究综合体）；Diamond Light Source（钻石光源）；Universität Bonn（波恩大学）
