Full text loading...
(Color online) (a)-(b) Top views of ZCG and ACG. Compressive strain is labeled as ɛ. Periodic boundary conditions are imposed in x-axis direction. Semi-infinite electrodes (shadowed) are clamped and applied with V b to calculate transport properties along z-axis. Thermal perturbations of 0.02 Å are applied on the middle 4 atoms overlapped with red circles. (c)-(d) Illustration of buckling generation in side views. Perturbed structures are relaxed and buckling occurs when ɛ exceeds the threshold strain ɛ T.
(Color online) Total energy (ΔE total) and maximum displacement (ΔH max) of ZCG (a) and ACG (b) versus compressive strain. Perturbed or unperturbed structures are labeled with prefix “P” or “UP.” Before the threshold strain is reached, ΔE total and ΔH max of perturbed and unperturbed structures are identical. After the threshold is reached, abrupt changes of ΔE total and ΔH max occur, indicating release of energy through bulking. Insets are the atomic positions after relaxation, which illustrate flat and buckled graphene, respectively.
(Color online) Transmission spectra of ZCG (a) and ACG (b) at Vb = 0.5 V under typical strain values: no strain, right before and after buckling threshold, and large strain (the percentage numbers). Insets are enlarged views near the Fermi level. Transmission differences between perturbed and unperturbed structures are represented as ΔT. Transmission of UPZCG is insensitive to strain, while that of PZCG is negatively correlated to strain when ɛ > 2.7%. Transmission of UPACG is negatively correlated to strain, while that of PACG is insensitive to strain when ɛ > 2.6%.
(Color online) (a) Resistance per unit length (R) at V b = 0.5 V versus compressive strain. UPZCG and UPACG have anisotropic R upon strain directions. While PZCG and PACG suppress the anisotropy after buckling occurs. (b) Average bond length (aAVE) versus compressive strain. aAVE of UPZCG and UPACG reduce linearly with strain while aAVE of PZCG and PACG increase abruptly at buckling threshold. Energy stored in compression process is released through recovering bond lengths to low strain states.
Article metrics loading...