Alapfogalmak
Andreev reflection enhances ∆T noise in metal-insulator-superconductor junctions, with thermal-noise dominating shot-noise.
Kivonat
The article explores the characterization of ∆T noise in 1D metal/insulator/superconductor junctions, focusing on Andreev reflection's impact. It discusses the dominance of thermal-noise over shot-noise, establishing a general bound independent of barrier strength. The study compares NIS and NIN junctions, highlighting the sensitivity of ∆T noise to changes in barrier strength and the role of Andreev reflection.
I. Introduction:
- Quantum noise analysis for quantum transport insights.
- Recent focus on ∆T quantum noise due to temperature gradient.
II. Theory:
- Hamiltonian formulation for NIS junction using BDG formalism.
- Wave functions description for normal metal and superconductor regions.
III. Results and Discussion:
- Comparison of ∆T noise behavior in transparent, intermediate, and tunnel limits.
- Analysis of dominant contributions from temperature difference to ∆T sh and ∆Tth noise.
IV. Analysis:
- Characteristics of quantum shot-noise and thermal-noise at different bias voltages.
V. Experimental Realization and Conclusion:
- Proposal for experimental setup to measure ∆T noise in NIS junctions.
Statisztikák
∆T thermal-noise (∆Tth) is always higher than or equal to ∆T shot-noise (∆T sh), i.e., ∆T sh/∆Tth ≤ 1.
∆NIS T /∆NIN T ≈ 2 in the transparent limit (Z → 0).
∆NIS T sh /∆NIN T sh ≈ 2 in the transparent limit (Z → 0).
∂f(E)/∂(kB ¯T) term dominates leading order contribution to total ∆NIS T noise with temperature difference (∆T).