Avalanche breakdown in GaTa4Se(8-x)Te(x) narrow-gap Mott insulators
1Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, Nantes, France.
Nature Communications
|April 18, 2013
Summary
Strong electric fields induce avalanche breakdown in Mott insulators, not Zener breakdown. This study reveals a universal power law for the threshold electric field, but with significantly longer avalanche delay times.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Solid-State Physics
Background:
- Mott transitions driven by electric fields are of increasing interest.
- Theoretical models suggest Zener breakdown in Mott insulators, but experimental evidence is limited.
Purpose of the Study:
- Investigate the mechanism of dielectric breakdown in narrow-gap Mott insulators GaTa4Se(8-x)Te(x).
- Compare experimental findings with theoretical predictions for Zener and avalanche breakdown.
Main Methods:
- Characterization of current-voltage (I-V) properties of GaTa4Se(8-x)Te(x) under varying electric fields.
- Analysis of the threshold electric field (Eth) and avalanche delay times.
Main Results:
- Dielectric breakdown in GaTa4Se(8-x)Te(x) follows an avalanche mechanism, not Zener breakdown.
- The threshold electric field (Eth) scales with the Mott-Hubbard gap (Eg) following Eth ∝ Eg^(2.5).
- Observed avalanche delay times are orders of magnitude longer than in conventional semiconductors.
Conclusions:
- Electric fields induce localized insulator-to-metal Mott transitions.
- These transitions form conductive domains that grow into filamentary paths, leading to avalanche breakdown.
- The findings challenge existing models and highlight unique breakdown dynamics in Mott insulators.
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