Fig. 4: The mechanical modulation of current rectifying in CIPS via the AFM tip force.
From: Manipulation of current rectification in van der Waals ferroionic CuInP2S6
a The I–V curves with a voltage sweeping of 0 V→+ 5 V→−5 V→0 V measured at a sweeping speed of 2 V/s. The number 1-4 denotes the sweeping sequence in a full cycle. The initial tip compressive force of 0.35 μN is set to the contact force between tip and nanoflakes. b The I–V curves with a voltage sweeping (0 V→+5 V→−5 V→0 V) at a sweeping speed of 2 V/s, but with different tip compressive force: 0.35 μN, 0.70 μN, 1.40 μN, 2.80 μN, 4.20 μN. c The current in ON state at ±5 V versus tip force. d–f The I–V data in ON state in positive (red) and negative voltage (blue) at different tip force is simulated (black line) by the modified thermionic emission theory; g, h the piezoelectric field (Ez-piezo) and flexoelectric field (Ez-flexo) in CIPS flakes obtained from theoretical calculations with a tip-force model under a tip force of 4.20 μN, respectively. i A consecutive write (±5 V) and read (±3 V) voltage pulses measurement at a constant tip force of 4.20 μN. A large positive/negative voltage pulse in writing operation leads to the positive/negative rectification (PR/NR) in the small voltage reading operation.
