Effects of finite superconducting coherence lengths and of phase gradients in topological SN and SNS junctions and rings

Polariton devices offer multiple advantages compared to conventional semiconductor devices. The bosonic nature of exciton polaritons offers opportunity of realisation of polariton lasers: coherent light sources based on bosonic condensates of polaritons. The final state stimulation of any transition feeding a polariton condensate has been used in many proposals such as for terahertz lasers based on polariton lasers. Furthermore, large coherence lengths of exciton-polaritons in microcavities open the way to realisation of polariton transport devices including transistors and logic gates. Being bosonic spin carriers, exciton-polaritons may be used in spintronic devices and polarisation switches. This chapter offers an overview on the existing proposals for polariton devices.

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Measurement of Laser Linewidths and Coherence Lengths using a Frequency Counter

2004 Conference on Precision Electromagnetic Measurements ◽

10.1109/cpem.2004.305541 ◽

2004 ◽

Author(s):

Jean-francois Cliche ◽

Michel Tetu

Keyword(s):

Frequency Counter ◽

Coherence Lengths

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THE VAN HOVE SINGULARITY IN HIGH Tc SUPERCONDUCTORS

International Journal of Modern Physics B ◽

10.1142/s0217979295000434 ◽

1995 ◽

Vol 09 (09) ◽

pp. 1067-1080 ◽

Cited By ~ 5

Author(s):

M.L. HORBACH ◽

H. KAJÜTER

Keyword(s):

Energy Scale ◽

Measured Temperature ◽

Van Hove Singularity ◽

High Tc Superconductors ◽

Electronic Density ◽

High Tc ◽

Scattering Rate ◽

Weakly Coupled ◽

Coherence Lengths

Experimental indications for the role of the van Hove singularity (vHs) in the electronic density of states of high Tc superconductors are discussed. It is argued that (i) like the resistivity, the measured temperature and doping dependences of the normal state electronic specific heat of YBCO are consistent with the existence of a vHs and (ii) the doping dependence of Tc in the underdoped and optimally doped regimes may be accounted for mainly by a vHs. Further, we discuss the suppression of the quasiparticle scattering rate below Tc, and the coherence lengths in the hole-doped materials and NCCO. Assuming that the same mechanism for superconductivity operates in the electron-doped and the hole-doped cuprates, we argue that the bosonic mode that causes the superconductivity is strongly influenced by the doping in the overdoped regime. We further argue that this boson involves an energy scale larger than that of phonons and is only weakly coupled to the charge carriers.

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Spin and phase coherence lengths in InAs wires with diffusive boundary scattering

Physical Review B ◽

10.1103/physrevb.88.205407 ◽

2013 ◽

Vol 88 (20) ◽

Cited By ~ 9

Author(s):

R. L. Kallaher ◽

J. J. Heremans ◽

W. Van Roy ◽

G. Borghs

Keyword(s):

Phase Coherence ◽

Boundary Scattering ◽

Diffusive Boundary ◽

Coherence Lengths

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Andreev bound states in superconducting films and confined superfluid 3 He

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2015.0144 ◽

2018 ◽

Vol 376 (2125) ◽

pp. 20150144 ◽

Cited By ~ 3

Author(s):

Anton B. Vorontsov

Keyword(s):

Bound States ◽

Surface States ◽

Surface Region ◽

Theme Issue ◽

Confined Geometry ◽

Andreev Bound States ◽

Broken Symmetries ◽

Parent State ◽

Open Questions ◽

Coherence Lengths

This paper reviews confinement-driven phase transitions in superconductors and Bardeen–Cooper–Schrieffer superfluids, and the appearance in thin films of new phases that break the time-reversal or translational symmetry. The origins of the new phases are closely tied to the Andreev scattering processes involving particle-hole conversions that create surface quasiparticle states with energies inside the superconducting gap. Restructuring of the low-energy spectrum in the surface region of several coherence lengths ξ 0 results in large spatial variations of the superconducting order parameter. In confined geometry, such as slabs, films, pores or nano-dots, with one or more physical dimensions D ∼10 ξ 0 , the Andreev bound states can dominate properties of a superconductor, leading to modified experimental signatures. They can significantly change the energy landscape, and drive transitions into new superconducting phases. The new phases are expected in a variety of materials, from singlet d -wave superconductors to multi-component triplet superfluid 3 He, but properties of the new phases will depend on the symmetry of the parent state. I will highlight the connection between the Andreev surface states and confinement-stabilized phases with additional broken symmetries, describe recent progress and open questions in the theoretical and experimental investigation of superfluids in confined geometry. This article is part of the theme issue ‘Andreev bound states’.

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