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Jumps in current-voltage characteristics in disordered films.
Boris L Altshuler1, Vladimir E Kravtsov, Igor V Lerner
1Physics Department, Columbia University, 538 West 120th Street, New York, New York 10027, USA.
Physical Review Letters
|June 13, 2009
Summary
Giant current jumps in disordered films are explained by electron overheating, creating two stable states: low-resistive (overheated) and high-resistive (less heated). This bistability depends on inefficient electron cooling and steep resistance-temperature curves.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Electrical Engineering
Background:
- Disordered thin films of Indium Oxide (InO), Titanium Nitride (TiN), and Yttrium Silicon (YSi) exhibit unusual current-voltage (I-V) characteristics.
- Giant jumps in current at finite voltages suggest a complex underlying physical mechanism beyond simple resistive behavior.
Purpose of the Study:
- To elucidate the physical mechanism behind the observed current jumps and voltage bistability in disordered InO, TiN, and YSi films.
- To develop a theoretical model that quantitatively explains the experimental I-V characteristics without adjustable parameters.
Main Methods:
- Analysis of experimental current-voltage (I-V) characteristics in disordered films.
- Modeling electron overheating and bistability based on inefficient electron cooling.
- Incorporation of the temperature dependence of equilibrium resistance (R(T)) and phonon-mediated electron cooling, considering disorder suppression.
Main Results:
- The observed current jumps and bistability are attributed to electron overheating, leading to two distinct resistive states.
- A low-resistive state arises from overheated electrons, while a high-resistive state results from less heating under the same applied voltage.
- The model accurately predicts experimental I-V curves, demonstrating quantitative agreement without adjustable parameters, provided electron cooling is inefficient and R(T) is sufficiently steep.
Conclusions:
- Electron overheating is the primary cause of the observed current bistability in disordered InO, TiN, and YSi films.
- The findings highlight the critical role of inefficient electron cooling and the material's R(T) dependence in enabling this phenomenon.
- Proposed experiments can further validate the electron overheating model and its implications for understanding transport in disordered materials.
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