Liu Lina, Ji Yujin, Bianchi Marco, Hus Saban M, Li Zheshen, Balog Richard, Miwa Jill A, Hofmann Philip, Li An-Ping, Zemlyanov Dmitry Y, Li Youyong, Chen Yong P
Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA.
Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA.
Nat Mater. 2024 Oct;23(10):1339-1346. doi: 10.1038/s41563-024-01987-w. Epub 2024 Aug 27.
Most two-dimensional (2D) materials experimentally studied so far have hexagons as their building blocks. Only a few exceptions, such as PdSe, are lower in energy in pentagonal phases and exhibit pentagons as building blocks. Although theory has predicted a large number of pentagonal 2D materials, many of these are metastable and their experimental realization is difficult. Here we report the successful synthesis of a metastable pentagonal 2D material, monolayer pentagonal PdTe, by symmetry-driven epitaxy. Scanning tunnelling microscopy and complementary spectroscopy measurements are used to characterize this material, which demonstrates well-ordered low-symmetry atomic arrangements and is stabilized by lattice matching with the underlying Pd(100) substrate. Theoretical calculations, along with angle-resolved photoemission spectroscopy, reveal monolayer pentagonal PdTe to be a semiconductor with an indirect bandgap of 1.05 eV. Our work opens an avenue for the synthesis of pentagon-based 2D materials and gives opportunities to explore their applications such as multifunctional nanoelectronics.
到目前为止，大多数经过实验研究的二维（2D）材料都以六边形为基本结构单元。只有少数例外，例如PdSe，在五边形相时能量更低，并以五边形作为基本结构单元。尽管理论上已经预测出大量的五边形二维材料，但其中许多都是亚稳态的，难以通过实验实现。在此，我们报告了通过对称驱动外延成功合成一种亚稳态五边形二维材料——单层五边形PdTe。利用扫描隧道显微镜和互补光谱测量对该材料进行表征，结果表明其具有排列有序的低对称性原子结构，并且通过与底层Pd(100)衬底的晶格匹配得以稳定。理论计算以及角分辨光电子能谱显示，单层五边形PdTe是一种间接带隙为1.05 eV的半导体。我们的工作为基于五边形的二维材料的合成开辟了一条途径，并为探索其在多功能纳米电子学等领域的应用提供了机会。
