  In the present study, molecular dynamics (MD) simulations have been performed
to understand the effect of nanowire size, temperature and strain rate on the
variations in dislocation density and deformation mechanisms in $<$100$>$ Cu
nanowires. The nanowire size has been varied in the range 1.446-43.38 nm with a
constant length of 21.69 nm. Different temperatures varying from 10 K to 700 K
and strain rates in the range of $5 \times 10^7$ - $1 \times 10^9$ s$^{-1}$
have been considered. For all the conditions, the variations in dislocation
density $(\rho)$ has been calculated as a function of strain. The results
indicate that the variations in dislocation density exhibits two stages
irrespective of the conditions: (i) dislocation exhaustion at small strains
followed by (ii) dislocation starvation at high strains. However, with
decreasing size and increasing temperature, the rate of dislocation exhaustion
increases, which results in early transition from dislocation exhaustion stage
to dislocation starvation stage. Similarly, with increasing strain rate, the
rate of dislocation exhaustion and also the transition strain increases.
