Table 1.

Comparative analysis of the models

Model	Device type	State variable	Control mechanism	Threshold exists	Supports boundary effects	Simulation compatible
Chua model [1, 2]	Generic	Flux or charge	Current	NA	NA	NA
Linear ion drift [3]	Bipolar	0 ≤ w ≤ D Doped region physical width	Current	No	External window functions	Possible with SPICE
Non-linear ion drift [46, 68]	Bipolar	0 ≤ w ≤ 1 Doped region normalized width	Voltage	No	External window functions	No
Exponential [69]	Bipolar	Switching speed	Voltage	No	Yes	No
Simmons tunneling barrier [70–72]	Bipolar	aoff ≤ w ≤ aon Undoped region width	Current	No	No	SPICE
Yakopcic [73, 74]	Bipolar	0 ≤ w ≤ 1 Not explained physically	Voltage	Yes	External window functions	SPICE/Verilog/MAPP
TEAM [75, 76]	Bipolar	xon ≤ x ≤ xoff Undoped region width	Current	Current	Implicit window functions	SPICE/Verilog/MAPP
VTEAM [77]	Bipolar	xon ≤ x ≤ xoff Undoped region width	Voltage	Voltage	Implicit window functions	SPICE/Verilog/MAPP
ASU/Stanford [78–81]	Bipolar	Filament gap (g)	Voltage	Temperature	No	SPICE/Verilog/MAPP
Filament dissolution [82–86]	Unipolar	Concentration of ions	Voltage	Temperature	No	COMSOL
Physical electro thermal [87]	Bipolar	Concentration of ions	Voltage	Temperature	Practically yes	COMSOL
Bocquet unipolar [90]	Unipolar	Concentration of ions	Voltage	Temperature	Yes	COMSOL/SPICE
Bocquet bipolar [91, 92]	Bipolar	CF radius	Voltage	Temperature	Yes	SPICE
Gonzalez-Cordero [93]	Bipolar	CF radius (top and bottom)	Voltage	Temperature	Yes	SPICE