Nature 453, 80–83 (2008)

In Fig. 2a of this Letter, the resistance for the right-hand element of the bottom circuit should be ROFF(1 - w/D), instead of the shown value ROFFw/D. Also, the correct value of window function should be w(D - W)/D2, rather than w(1 - W)/D2. All simulation results presented in the paper use the correct formulae.