“…For unipolar devices, the selector can be a diode, but for bipolar memristors, the selector needs to have a large and roughly symmetric i–v nonlinearity in order to block current flow in either direction at low voltage magnitudes while allowing a much larger (e.g., >100×) current at higher voltages. Therefore, two‐terminal selectors with a scalability comparable to that of memristors are essential to realize the large array sizes needed to be competitive with the bit densities of alternate NVM technologies 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13. Accordingly, a significant effort has recently introduced a variety of new selectors, including an Ovonic threshold switch,11, 14 a mixed ionic–electronic conductor,9 an insulator–metal‐transition5, 15, 16 selector, tunneling devices,12, 17, 18, 19, 20 and others 6, 13…”