Abstract
Crossover from Mott variable-range-hopping conductivity to the Coulomb-gap Efros-Shklovskii (ES) variable-range-hopping conductivity has been observed in amorphous indium oxide films. The hopping exponent x0.56 in the activated Coulomb-gap regime is greater than the x=0.50 value predicted by Efros and Shklovskii. The experimental value of x0.56 is in excellent agreement with the computational calculations of Mobius and Richter, who suggest that x=0.55. The experimental ratios for TMott/TES54 are in close agreement with the prediction of Castner that TMott/TES=81. Experimental values for the crossover temperatures, which separate the two hopping regimes, are consistent with predicted values. The Coulomb-gap energy CG is estimated to range from a few tenths of a meV for films close to the metal-insulator transition to several meVs for films quite deep in the insulating regime.
| Original language | English |
|---|---|
| Pages (from-to) | 3599-3603 |
| Number of pages | 5 |
| Journal | Physical Review B |
| Volume | 44 |
| Issue number | 8 |
| DOIs | |
| State | Published - 1991 |