Conductance fluctuations in chaotic systems with tunnel barriers
arXiv:1108.5091 · doi:10.1103/PhysRevB.85.024302
Abstract
Quantum effects are expected to disappear in the short-wavelength, semiclassical limit. As a matter of fact, recent investigations of transport through quantum chaotic systems have demonstrated the exponential suppression of the weak localization corrections to the conductance and of the Fano factor for shot-noise when the Ehrenfest time exceeds the electronic dwell time. On the other hand, conductance fluctuations, an effect of quantum coherence, retain their universal value in the limit of the ratio of Ehrenfest time over dwell time to infinity, when the system is ideally coupled to external leads. Motivated by this intriguing result we investigate conductance fluctuations through quantum chaotic cavities coupled to external leads via (tunnel) barriers of arbitrary transparency. Using the trajectory-based semiclassical theory of transport, we find a linear Ehrenfest time-dependence of the conductance variance showing a nonmonotonous, sinusoidal behavior as a function of the transperancy. Most notably, we find an increase of the conductance fluctuations with the Ehrenfest time, above their universal value, for the transparency less than 0.5. These results, confirmed by numerical simulations, show that, contrarily to the common wisdom, effects of quantum coherence may increase in the semiclassical limit, under special circumstances.
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- Anti-correlation for Conductance Fluctuations in Chaotic Quantum Dots
- Transport moments and Andreev billiards with tunnel barriers
- Combinatorial theory of the semiclassical evaluation of transport moments II: Algorithmic approach for moment generating functions
- Semiclassical treatment of quantum chaotic transport with a tunnel barrier
- Spin Chaos Manifestation in a Driven Quantum Billiard with Spin-Orbit Coupling
- Statistics of quantum transport in weakly non-ideal chaotic cavities
- Semiclassical theory of speckle correlations
- Exponentially small quantum correction to conductance
- Quantum transport in chaotic cavities with tunnel barriers
- Electronic transport in three-terminal chaotic systems with a tunnel barrier