Enhanced Andreev Reflection in Flat-Band Systems: Wave Packet Dynamics, DC Transport and the Josephson Effect

Abstract

We investigate Andreev reflection (AR) in a proximity-induced normal-superconductor (NS) junction within the extended $\alpha -{\mathcal{T}}_3$ lattice, emphasizing the impact of flat bands on AR. Our findings reveal that flat bands significantly enhance AR. Through wave packet dynamics, we track the real-time evolution of quasi-particle wave packets across the junction, providing deeper insight into electron-hole conversion. Notably, the combination of band flatness and anisotropic dispersion in the $k_x-k_y$ plane induces an electronic analog of Goos-Hänchen (GH) shifts at the NS interface, exhibiting directional asymmetry along the junction. This asymmetry leads to a Hall-like response in Josephson junction in SNS geometry, where transport across the junction region is dominated by the quasi-flat bands.

13 pages, 11 figures

References in corpus (64)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Magic-angle graphene superlattices: a new platform for unconventional superconductivity
• Correlated Insulator Behaviour at Half-Filling in Magic Angle Graphene Superlattices
• Andreev reflection and Klein tunneling in graphene
• Majorana Fermion Induced Resonant Andreev Reflection
• Specular Andreev reflection in graphene
• Anisotropic behaviors of massless Dirac fermions in graphene under periodic potential
• From Andreev to Majorana bound states in hybrid superconductor-semiconductor nanowires
• Negative flat band magnetism in a spin-orbit coupled correlated kagome magnet
• Josephson effect in ballistic graphene
• Nearly flat band with Chern number C=2 on the dice lattice
• From dia- to paramagnetic orbital susceptibility of Dirac cones
• The role of critical current on point contact Andreev Reflection spectrum between a normal metal and a superconductor
• Andreev Level Qubit
• Superconductivity in twisted bilayer WSe${}_2$
• Phase-shifted Andreev levels in an altermagnet Josephson junction
• Gate-controlled BCS-BEC crossover in a two-dimensional superconductor
• Theoretical possibilities for flat-band superconductivity
• Photoinduced valley and electron-hole symmetry breaking in $\alpha$-$T_3$ lattice: The role of a variable Berry phase
• Floquet topological phase transition in $\alpha$-${\mathcal{T}}_3$ lattice
• Superconductivity and quantized anomalous Hall in rhombohedral graphene
• Josephson effect in graphene SBS junctions
• Emergent pseudospin-1 Maxwell fermions with a threefold degeneracy in optical lattices
• Dynamics of quasiparticle trapping in Andreev levels
• Unconventional phases in a Haldane model of dice lattice
• Josephson diode effect derived from short-range coherent coupling
• Random-matrix theory of Andreev reflection from a topological superconductor
• Andreev reflection in bosonic condensates
• Josephson effect in a Weyl SNS junction
• Generalized WKB theory for electron tunneling in gapped $\alpha -{\mathcal{T}}_3$ lattices
• Andreev bound states and $\pi$-junction transition in a superconductor / quantum-dot / superconductor system
• Correlated Electronic Structure and Incipient Flat Bands of the Kagome Superconductor CsCr3Sb5
• Nonequilibrium transport in mesoscopic multi-terminal SNS Josephson junctions
• Short Ballistic Josephson Coupling in Planar Graphene Junctions with Inhomogeneous Carrier Doping
• Super-Andreev reflection and longitudinal shift of pseudospin-one fermions
• Bi-stability in voltage-biased NISIN structures
• Flat-Band Enhanced Antiferromagnetic Fluctuations and Superconductivity in Pressurized CsCr${}_3$Sb${}_5$
• Spin-polarized Specular Andreev Reflections in Altermagnets
• 1/f critical current noise in short ballistic graphene Josephson junctions
• Majorana dc Josephson current mediated by a quantum dot
• Suppression of non-equilibrium quasiparticle transport in flat band superconductors
• Two-dimensional Josephson vortex lattice and anomalously slow decay of the Fraunhofer oscillations in a ballistic SNS junction with a warped Fermi surface
• Electrically charged Andreev modes in two-dimensional tilted Dirac cone systems
• Crossed Andreev reflection in collinear $p$-wave magnet/triplet superconductor junctions
• Spin-Hall current and spin polarization in an electrically biased SNS Josephson junction
• Quasiclassical theory of charge transport across mesoscopic normal metal-superconducting heterostructures with current conservation
• Electron beam splitting at topological insulator surface states and a proposal for electronic Goos-Hanchen shift measurement
• Superconducting critical temperature in the extended diffusive SYK model
• Goos-Hänchen-like shifts at metal/superconductor interface
• Gate control of superconductivity in mesoscopic all-metallic devices
• Magnomechanically controlled Goos-Hänchen shift in cavity QED
• Transport across junctions of pseudospin-one fermions
• Andreev reflection of massive pseudospin-1 fermions
• Tunable valley filtering in dynamically strained $\alpha$-${\mathcal{T}}_3$ lattices
• Effect of magnetic field on the electronic properties of an $\alpha$-$T_3$ ring
• Transverse Cooper-Pair Rectifier
• Tunable compact on-chip superconducting switch
• Electrical and thermal transport through $\alpha -T_3$ NIS junction
• Nodal Nematic Superconductivity in Multiple-Flat-Band Land
• Goos-Hänchen Shift and Photonic Spin Hall Effect in Semi-Dirac Material Heterostructures
• Superconducting junctions with flat bands
• Intertwined Magnetism and Superconductivity in Isolated Correlated Flat Bands
• Four-terminal Josephson junctions: diode effects, anomalous currents and transverse currents
• Nature of Andreev bound states in Josephson junctions of triple-point semimetals