We discuss bi-structures with one or two long bonds in the central part of the strained monoatomic chains appearing abruptly as a result of rigid bifurcations of the equilibrium state with increasing strain above some critical value. Bi-structures of this type were initially revealed in the model of the monoatomic chains with the Lennard-Jones interactions (L-J model). Such structures are universal because they must exist in the finite strained chains of any physical nature. We confirmed this statement for the strained chains of carbon and boron atoms with the aid of the density functional theory using results obtained in the simulation of the L-J model as initial approximation. The properties of these bi-structures, depending on the length of the chains, are investigated in detail. It is assumed that the abrupt change in the electrical properties of strained carbon and boron chains in the vicinity of the above bifurcations can be used to create nanodevices within the framework of straintronics.

我们讨论在应变单原子链的中心部分突然出现一个或两个长键的双结构，这是由于平衡态的刚性分叉而导致的，在某些临界值以上，应变增加。这种类型的双结构最初是在具有Lennard-Jones相互作用的单原子链模型（LJ模型）中揭示的。这样的结构是通用的，因为它们必须存在于任何物理性质的有限应变链中。我们借助密度泛函理论，使用在LJ模型的模拟中获得的结果作为初始近似值，证实了碳和硼原子的应变链的这一陈述。根据链的长度，对这些双结构的性质进行了详细研究。