Measurement of the inherent strength of carbon atomic chains

The intrinsic strength of freestanding carbon atomic chains was measured by in situ high-field mechanical testing of carbon atomic chains carried out inside a field-ion microscope. The determined breaking field strength corresponds to a tensile strength of carbon atomic chains at 5 K equal to 245 GPa. Carbon atomic chains also show exceptionally high-evaporation stability in electric fields up to 259 V/nm. The tensile strength of linear carbon chains significantly exceeds the tensile strength of known two-dimensional and three-dimensional carbon materials, including carbon nanotubes and graphene. Our results can be considered as direct experimental evidence for Pauling's prediction of bond stiffening with reduced atomic bond order.

Figure 1

Field ionization near a self-standing monoatomic chain anchored at the graphite parabolic tip. Blue dashed and solid lines show the electrical and critical surfaces, respectively.

Figure 2

Calculated variations in the field potential with distance from the electrical surface of a carbon chain.

Figure 3

Electric-field strength $F_{\mathrm{cr}}$ at the critical surface and the reduced radius ${\rho }_{\mathrm{cr}}$/ρ of the critical surface versus the ratio of operation voltage $V$ to the imaging gas ionization threshold voltage $V_0$.

Figure 4

Dependence of tensile stress on reduced operation voltage.

Figure 5

Helium field-ion images of the graphite nanotip with a surface formed by low-temperature field treatment at (a) evaporation voltages 827 V and (b) 941 V, intermediate voltage (c) 785 V, and ionization threshold voltage (d) $V_0$ $=$ 662 V.

Figure 6

The size dependence of the applied field for evaporation of carbon nano- and subnanotips at 0 K in two ionization states.

Figure 7

Potential-energy diagram showing the image-hump model of field evaporation for picometer-scale carbon wires.