Translation Symmetry Breakdown in Low-Dimensional Lattices of Pentagonal Rings

Abstract

The mechanism of translation symmetry breakdown in newly proposed low-dimensional carbon pentagon-constituted nanostructures (e.g., pentagraphene) with multiple sp(2)/sp(3) sublattices was studied by GGA DFT, DFTB, and model potential approaches. It was found that finite nanoclusters suffer strong uniform unit cell bending followed by breaking of crystalline lattice linear translation invariance caused by structural mechanical stress. It was shown that 2D sp(2)/sp(3) nanostructures are correlated transition states between two symmetrically equivalent bent structures. At DFT level of theory the distortion energy of the flakes (7.5 × 10(-2) eV/atom) is much higher the energy of dynamical stabilization of graphene. Strong mechanical stress prevents stabilization of the nanoclusters on any type of supports by either van der Waals or covalent bonding and should lead to formation of pentatubes, nanorings, or nanofoams rather than infinite nanoribbons or nanosheets. Formation of two-layered pentagraphene structures leads to compensation of the stress and stabilization of flat finite pentaflakes.

Two-dimensional hexagonal CrN with promising magnetic and optical properties: A theoretical prediction

“…63 Sometimes, due to the breakdown of translational symmetry for low-dimensional materials with non-equivalent sublattices, phonon calculations in periodic boundary conditions cannot be used to prove whether or not a low-dimensional crystalline lattice is a local or global minimum. 64 The force constants also can be affected by phonon-magnetic coupling or strong electron correlations and soft modes may take place in magnetic and/or correlated low-dimensional systems. 65,66 The newly proposed h-CrN is an example of a strongly correlated low-dimensional magnetic material with non-equivalent sublattices.…”

Electronic transport in penta-graphene nanoribbon devices using carbon nanotube electrodes: A computational study

“…Moreover, Zhang and coworkers [12] have reported the thermal and mechanical stability of pentagon-based carbon nanotubes (CNTs). Additionally, Avramov et al [25] have reported the binding energy per atom for (n, n) penta-graphene based carbon nanotubes (CNTs), confirming that the (7,7) penta-graphene based CNT is the most energetically stable structure. Pentagraphene is an attractive material for optoelectronic applications, because it is a semiconductor with a quasi-direct band gap.…”

Десорбция Водорода Из Пентаграфана

“…Оказывается, однако, что термоактивированный поворот димеров С2 инициирует образование дефектных участков, которые не остаются локализованными, а быстро распространяются на весь образец, приводя к его полному разрушению [11]. Еще одним препятствием на пути изготовления пентаграфена может стать сильный изгиб образцов в процессе роста и даже их сворачивание в пентатрубки под действием механических напряжений, создаваемых двумя подрешетками димеров С2 [12].…”