Cui Zhi-Hao, Jimenez-Izal Elisa, Alexandrova Anastassia N
Department of Chemistry and Biochemistry, University of California , Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States.
College of Chemistry and Molecular Engineering, Peking University , 100871 Beijing, China.
J Phys Chem Lett. 2017 Mar 16;8(6):1224-1228. doi: 10.1021/acs.jpclett.7b00275. Epub 2017 Mar 3.
Two-dimensional (2D) phases of boron are rare and unique. Here we report a new 2D all-boron phase (named the π phase) that can be grown on a W(110) surface. The π phase, composed of four-membered rings and six-membered rings filled with an additional B atom, is predicted to be the most stable on this support. It is characterized by an outstanding stability upon exfoliation off of the W surface, and unusual electronic properties. The chemical bonding analysis reveals the metallic nature of this material, which can be attributed to the multicentered π-bonds. Importantly, the calculated conductivity tensor is anisotropic, showing larger conductivity in the direction of the sheet that is in-line with the conjugated π-bonds, and diminished in the direction where the π-subsystems are connected by single σ-bonds. The π-phase can be viewed as an ultrastable web of aligned conducting boron wires, possibly of interest to applications in electronic devices.
二维（2D）硼相既稀有又独特。在此，我们报告一种可生长在W(110)表面的新型二维全硼相（命名为π相）。π相由四元环和填充有额外硼原子的六元环组成，预计在该衬底上最为稳定。其特点是从W表面剥离时具有出色的稳定性以及非同寻常的电子特性。化学键分析揭示了这种材料的金属性质，这可归因于多中心π键。重要的是，计算得到的电导率张量是各向异性的，在与共轭π键对齐的片层方向上显示出更大的电导率，而在π子系统通过单个σ键连接的方向上电导率降低。π相可被视为由排列整齐的导电硼线构成的超稳定网络，可能在电子器件应用中具有吸引力。
