Feng Baojie, Sugino Osamu, Liu Ro-Ya, Zhang Jin, Yukawa Ryu, Kawamura Mitsuaki, Iimori Takushi, Kim Howon, Hasegawa Yukio, Li Hui, Chen Lan, Wu Kehui, Kumigashira Hiroshi, Komori Fumio, Chiang Tai-Chang, Meng Sheng, Matsuda Iwao
Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Phys Rev Lett. 2017 Mar 3;118(9):096401. doi: 10.1103/PhysRevLett.118.096401. Epub 2017 Mar 2.
Honeycomb structures of group IV elements can host massless Dirac fermions with nontrivial Berry phases. Their potential for electronic applications has attracted great interest and spurred a broad search for new Dirac materials especially in monolayer structures. We present a detailed investigation of the β_{12} sheet, which is a borophene structure that can form spontaneously on a Ag(111) surface. Our tight-binding analysis revealed that the lattice of the β_{12} sheet could be decomposed into two triangular sublattices in a way similar to that for a honeycomb lattice, thereby hosting Dirac cones. Furthermore, each Dirac cone could be split by introducing periodic perturbations representing overlayer-substrate interactions. These unusual electronic structures were confirmed by angle-resolved photoemission spectroscopy and validated by first-principles calculations. Our results suggest monolayer boron as a new platform for realizing novel high-speed low-dissipation devices.
IV族元素的蜂窝状结构可以容纳具有非平凡贝里相位的无质量狄拉克费米子。它们在电子应用方面的潜力引起了极大的兴趣，并促使人们广泛寻找新的狄拉克材料，特别是在单层结构中。我们对β₁₂片层进行了详细研究，β₁₂片层是一种可以在Ag(111)表面自发形成的硼烯结构。我们的紧束缚分析表明，β₁₂片层的晶格可以以类似于蜂窝晶格的方式分解为两个三角形子晶格，从而容纳狄拉克锥。此外，通过引入代表覆盖层-衬底相互作用的周期性微扰，可以分裂每个狄拉克锥。这些不寻常的电子结构通过角分辨光电子能谱得到证实，并通过第一性原理计算得到验证。我们的结果表明，单层硼是实现新型高速低耗散器件的新平台。
