of length ai , and separated by L⇥ i (a function of L and ai ) and is given by Eqn.(3), and the third term is the self energy of the dislocation segments that form the kink-jog pair. In Eqns. (2) and (3), µ = 42 GPa is the shear modulus of bulk copper and b = aCu ⇤ 2 is the magnitude of the Burgers vector of all the dislocation segments; aCu is the 0 K lattice constant of copper. From simulations, we obtain a1 = aCu ⇤ 3 , a2 = aCu ⇤ 2 , and L = 3aCu ⇤ 2 . Energy expressions for all the states in our simulations are readily obtained as a combination of Eqns. (2) and (3) with appropriate values for the variables L, L⇥ i , and ai . W(L, a, {L⇥ i }, {ai }) = 2 Wdis inter (L, ⇥, a) + ⌥ i Wjog inter (L⇥ i , ai ) + ⌥ i 2 µb2ai 4⇧(1 ⌅) ln ai b ⇥ Wdis inter (L, ⇥, a) = µb2 4⇧ ⇧ ⇧ L2 + a2 L a + L ln ⇤ 2L ⇧ L2 + a2 + L ⌅⌃ Wjog inter (L, a) = µb2 4⇧(1 ⌅) ⇧ 2L 2 ⇧ L2 + a2 2a ln ⇤ L ⇧ L2 + a2 + a ⌅⌃ WMEP A B (L, a, {L⇥ i }, {ai }, s) = WA B(L, a, {L⇥ i }, {ai }, s) + A⇥GSF (s) The parameter is related to the dislocation (in this case, jogs and kinks) core radius and can not be estimated within the linear elastic theory of dislocations. We obtain = 0.448 by ﬁtting the energy, E = 0.27 eV, of the kink pair conﬁguration corresponding to the conﬁguration in Fig. 1[schematic of the kink pair is marked in Fig. 5(b) and] from our • α can not be determined with in linear elastic theory of dislocations • α = 0.458 is obtained by fitting the expression for formation energy of a thermal kink pair from simulations (ΔE = 0.27 eV) Thermal kink pair configuration Dislocation model for point defect migration b1 !1 Set 2 Set 1 a L a2 a1 I1 b1 !1 Set 1 Set 2 a1 a2 L L b1 !1 Set 1 Set 2 b 3L (a) (b) (c) J. P. Hirth and J. Lothe, Theory of Dislocations, (Wiley, New York, 1982)