Content of SPECIAL TOPIC—The third carbon: Carbyne with one-dimensional sp-carbon in our journal

Published in last 1 year |  In last 2 years |  In last 3 years |  All Please wait a minute... For selected: Download citations EndNote Ris BibTeX Toggle thumbnails Select Chemical bonding in representative astrophysically relevant neutral, cation, and anion HCnH chains Ioan Baldea Chin. Phys. B, 2022, 31 (12): 123101.   DOI: 10.1088/1674-1056/ac9b04 Abstract （190）   HTML （3）    PDF （6583KB）（161）       Knowledge map    Most existing studies assign a polyynic and cumulenic character of chemical bonding in carbon-based chains relying on values of the bond lengths. Building on our recent work, in this paper we add further evidence on the limitations of such an analysis and demonstrate the significant insight gained via natural bond analysis. Presently reported results include atomic charges, natural bond order and valence indices obtained from ab initio computations for representative members of the astrophysically relevant neutral and charged HC2k/2k+1H chain family. They unravel a series of counter-intuitive aspects and/or help naive intuition in properly understanding microscopic processes, e.g., electron removal from or electron attachment to a neutral chain. Demonstrating that the Wiberg indices adequately quantify the chemical bonding structure of the HC2k/2k+1H chains—while the often heavily advertised Mayer indices do not—represents an important message conveyed by the present study. Select Nitrogen-tailored quasiparticle energy gaps of polyynes Kan Zhang(张侃), Jiling Li(李继玲), Peitao Liu(刘培涛), Guowei Yang(杨国伟), and Lei Shi(石磊) Chin. Phys. B, 2022, 31 (12): 123102.   DOI: 10.1088/1674-1056/ac8cde Abstract （210）   HTML （4）    PDF （1745KB）（172）       Knowledge map    Polyyne, an sp1-hybridized linear allotrope of carbon, has a tunable quasiparticle energy gap, which depends on the terminated chemical ending groups as well as the chain length. Previously, nitrogen doping was utilized to tailor the properties of different kinds of allotrope of carbon. However, how the nitrogen doping tailors the properties of the polyyne remains unexplored. Here, we applied the GW method to study the quasiparticle energy gaps of the N-doped polyynes with different lengths. When a C atom is substituted by an N atom in a polyyne, the quasiparticle energy gap varies with the substituted position in the polyyne. The modification is particularly pronounced when the second-nearest-neighboring carbon atom of a hydrogen atom is substituted. In addition, the nitrogen doping makes the Fermi level closer to the lowest unoccupied molecular orbital, resulting in an n-type semiconductor. Our results suggest another route to tailor the electronic properties of polyyne in addition to the length of polyyne and the terminated chemical ending groups. Select Accurate theoretical evaluation of strain energy of all-carboatomic ring (cyclo[2n]carbon), boron nitride ring, and cyclic polyacetylene Tian Lu(卢天), Zeyu Liu(刘泽玉), and Qinxue Chen(陈沁雪) Chin. Phys. B, 2022, 31 (12): 126101.   DOI: 10.1088/1674-1056/ac873a Abstract （274）   HTML （5）    PDF （2910KB）（83）       Knowledge map    Cyclocarbon fully consists of sp-hybridized carbon atoms, which shows quite unusual electronic and geometric structures compared to common molecules. In this work, we systematically studied strain energy (SE) of cyclocarbons of different sizes using regression analysis method based on electronic energies evaluated at the very accurate DLPNO-CCSD(T)/cc-pVTZ theoretical level. In addition, ring strain of two systems closely related to cyclocarbon, boron nitride (BN) ring, and cyclic polyacetylene (c-PA), is also explored. Very ideal relationships between SE and number of repeat units ($n)$ are built for cyclo[2$n$]carbon, B$_{n}$N$_{n}$, and [2$n$]c-PA as ${\rm SE} = 555.0\cdot n^{-1}$, 145.1$\cdot n^{-1}$, and 629.8$\cdot n^{-1}$ kcal$\cdot $mol$^{-1}$, respectively, and the underlying reasons of the difference and similarity in their SEs are discussed from electronic structure perspective. In addition, force constant of harmonic potential of C-C-C angles in cyclocarbon is derived based on SE values, the result is found to be 56.23 kcal$\cdot $mol$^{-1}\cdot $rad$^{-2}$. The possibility of constructing homodesmotic reactions to calculate SEs of cyclocarbons is also explored in this work, although this method is far less rigorous than the regression analysis method, its result is qualitatively correct and has the advantage of much lower computational cost. In addition, comparisons show that $\omega $B97XD/def2-TZVP is a good inexpensive alternative to the DLPNO-CCSD(T)/cc-pVTZ for evaluating energies used in deriving SE, while the popular and very cheap B3LYP/6-31G(d) level should be used with caution for systems with global electron conjugation such as c-PA. Select Large-scale synthesis of polyynes with commercial laser marking technology Liang Fang(房良), Yanping Xie(解燕平), Shujie Sun(孙书杰), and Wei Zi(訾威) Chin. Phys. B, 2022, 31 (12): 126803.   DOI: 10.1088/1674-1056/ac7cd1 Abstract （306）   HTML （9）    PDF （3057KB）（118）       Knowledge map    The space-confined synthesis method has been an efficient way for the preparation of linear carbon chains. However, the large-scale preparation of linear carbon chains still faces many challenges due to the lack of methods for the large-scale synthesis of precursors, such as short carbon chains (polyynes), and regulation technology for the transport of reactants in one-dimensional space. Here, we report a facile method for the rapid preparation of polyynes in large quantities using a commercial laser marking machine. Spectroscopic characterizations show that a large number of polyynes, such as C8H2, C10H2, C12H2, and C14H2, can be produced by ablating the graphite plate immersed in the organic liquid using a laser marking machine. The results of in situ Raman spectroscopy investigation of C2nH2-filled single-walled carbon nanotubes further confirm that a variety of polyyne molecules are synthesized. Meanwhile, in situ Raman spectroscopy also shows that the local heating treatment can accelerate the filling process of C2nH2 into one-dimensional channels. This work provides new insights into the study of linear carbon chains and space-confined synthesis methods. Select Conformational change-modulated spin transport at single-molecule level in carbon systems Yandong Guo(郭艳东), Xue Zhao(赵雪), Hongru Zhao(赵鸿儒), Li Yang(杨丽), Liyan Lin(林丽艳), Yue Jiang(姜悦), Dan Ma(马丹), Yuting Chen(陈雨婷), and Xiaohong Yan(颜晓红) Chin. Phys. B, 2022, 31 (12): 127201.   DOI: 10.1088/1674-1056/ac872d Abstract （285）   HTML （9）    PDF （1451KB）（130）       Knowledge map    Controlling the spin transport at the single-molecule level, especially without the use of ferromagnetic contacts, becomes a focus of research in spintronics. Inspired by the progress on atomic-level molecular synthesis, through first-principles calculations, we investigate the spin-dependent electronic transport of graphene nanoflakes with side-bonded functional groups, contacted by atomic carbon chain electrodes. It is found that, by rotating the functional group, the spin polarization of the transmission at the Fermi level could be switched between completely polarized and unpolarized states. Moreover, the transition between spin-up and spin-down polarized states can also be achieved, operating as a dual-spin filter. Further analysis shows that, it is the spin-dependent shift of density of states, caused by the rotation, that triggers the shift of transmission peaks, and then results in the variation of spin polarization. Such a feature is found to be robust to the length of the nanoflake and the electrode material, showing great application potential. Those findings may throw light on the development of spintronic devices. Select Extraordinary mechanical performance in charged carbyne Yong-Zhe Guo(郭雍哲), Yong-Heng Wang(汪永珩), Kai Huang(黄凯), Hao Yin(尹颢), and En-Lai Gao(高恩来) Chin. Phys. B, 2022, 31 (12): 128102.   DOI: 10.1088/1674-1056/ac7bf8 Abstract （280）   HTML （11）    PDF （9253KB）（186）       Knowledge map    Carbyne, the linear chain of carbon, promises the strongest and toughest material but possesses a Peierls instability (alternating single-bonds and triple-bonds) that reduces its strength and toughness. Herein, we computationally found that the gravimetric strength, strain-to-failure, and gravimetric toughness can be improved from 74 GPa·g-1·cm3, 18%, and 9.4 kJ·g-1 for pristine carbyne to the highest values of 106 GPa·g-1·cm3, 26%, and 19.0 kJ·g-1 for carbyne upon hole injection of +0.07 e/atom, indicating the charged carbyne with record-breaking mechanical performance. Based on the analyses of the atomic and electronic structures, the underlying mechanism behind the record-breaking mechanical performance was revealed as the suppressed and even eliminated bond alternation of carbyne upon charge injection.