Table 4. Current–Voltage Characteristics of Cyclic Compounds.
| DFT-NEGF
calculations |
model
calculations |
||||||
|---|---|---|---|---|---|---|---|
| compound | SRa (0 V) | SRa (1 V) | RRb | E0c (eV) | Γd (meV) (= (ΓRΓL)1/2) | ε– (ε+)e | ΓR/ΓLf |
| 4-OFF | 718 | 13 | 11.8 | 0.46 | 5.5 | 7.5 (104.3) | 13.9 |
| 4-ON | 1.0 | 0.08 | 55.0 | 2.4 (2.4) | 1.0 | ||
| 8-OFF | 503 | 45 | 1.0 | 0.50 | 7.7 | 24.5 (24.5) | 1.0 |
| 8-ON | 1.4 | 0.16 | 36.9 | 7.2 (5.0) | 0.7 | ||
| 12-OFF | 203 | 4 | 8.7 | 0.49 | 4.3 | 12.8 (74.2) | 5.8 |
| 12-ON | 1.1 | 0.06 | 5.7 | 4.3 (2.5) | 0.6 | ||
| 16-OFF | 314 | 17 | 1.6 | 0.54 | 10.1 | 16.7 (43.4) | 2.6 |
| 16-ON | 1.1 | 0.09 | 18.7 | 3.4 (2.8) | 0.8 | ||
| 17-OFF | 1157 | 41 | 2.3 | 0.52 | 13.9 | 3.6 (7.6) | 2.1 |
| 17-ON | 1.2 | 0.08 | 50.0 | 2.5 (2.6) | 1.1 | ||
a
Conductance ON/OFF switching ratio.
b
Rectifying ratio, calculated as the ratio between the current at bias voltage +1 and −1 V.
c
Distance between the most conducting level and EF (V = 0).
d
Effective coupling between the most conducting level and the electrodes.
e
Proportionally factor for movement of the conducting level under bias (Ẽ0 = E0 ± (V/ε±) for ± V, ε+ = ε–ΓR/ΓL).
f
A measure of the unsymmetry of the effective coupling to the electrodes.