A very special conductor! Notice the size of the conductor. What was done to the conductor in (c ) and (e) . The graph in (b) looks fairly normal , constant resistance , ohmic in nature.
In (d) the resistance is higher when voltage is negative.
In (f) the current cease to flow when the voltage is negative.
By bending the wire (nanowire) a diode is created. It is referred to as nano piezotronic diode. Read more in delicious.
