C.H.Wong, J. Y. Dai, E. A. Buntov, V. N. Rychkov, M. B. Guseva, A. F. Zatsepin, Effect of symmetry on electronic DOS, peierls transition and elastic modulus of carbon nanowires

Research Article 2017, 8(12), 1161-1165 Advanced Materials Letters

A Monte Carlo arithmetic method is utilized to investigate the Peierls transition in the linear and circular carbon nanowire respectively. The carbon nanowires interacting with the 6 nearest neighbors in hexagonal structure are spaced by 0.3 nm. Despite the Peierls transition of the linear carbon nanowires is unaffected by the Van der Waal’s force, we discovered that the Peierls transition temperature of the isolated curved nanowire is raised to 910K under curvature. Based on the simulation results, the fluctuation of the atomic position of the atoms are stronger near to the free end boundary condition. Applying stress on the interstitial doped carbon nanowire array examines the elastic modulus which shows above 6TPa. The geometrical effect on the electronic density of states of the kink structural carbon chain is simulated by Harris functional in combination with Local Density Approximation. Two different lengths of branches A and B, are occupied alternatively to generate the asymmetric carbon chain. The ratio of the asymmetric branch length, RAB = A / B, plays an important role in the electronic density of states DOS around Fermi level F E . The highest DOS(EF) occurs if the RAB equals to 2 and while the Fermi level coincides with the Von-Hove singularity at RAB = 3.

Copyright © 2017 VBRI Press.

Despite the Van Der Waal’s force shows no influence onthe Peierls transition temperature of the carbon nanowire, the increase of the Peierls transition temperature from 500 K to 910 K is observed under curvature. A weak reinforcement in the elastic modulus of the carbon chain is confirmed by the Monte Carlo method at various levels of interstitial doping. The atomic coordinate of the carbon atoms at equilibrium along the short nanowire is disturbed by the boundary condition. The carbon atoms occupied denser at the fixed boundary case. On the other hand, we
have investigated the electronic density of states of the carbon chain under symmetric and asymmetric branch. Instead of compressing the sample or injecting gate voltage, a guideline of tuning the Fermi level to the Von- Hove singularity in the electronic density of state is provided by kink structure. According to our simulation, closing the gap between the Fermi-level and the Von- Hove singularity by the generation of asymmetric kink structure is more wisely than the design of symmetric carbon chain. Interestingly the Fermi-level of the carbon chain is intrinsically aligned at the Von-Hove singularityif the ratio of the asymmetric branch length is 3 (relative to 134pm).

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