Tip-induced Superconductivity

Abstract

It is widely believed that topological superconductivity, a hitherto elusive phase of quantum matter, can be achieved by inducing superconductivity in topological materials. In search of such topological superconductors, certain topological insulators (like, Bi${}_2$Se${}_3$) were successfully turned into superconductors by metal-ion (Cu, Pd, Sr, Nb etc. ) intercalation. Superconductivity could be induced in topological materials through applying pressure as well. for example, a pressure-induced superconducting phase was found in the topological insulator Bi${}_2$Se${}_3$. However, in all such cases, no conclusive signature of topological superconductivity was found. In this review, we will discuss about another novel way of inducing superconductivity in a non-superconducting topological material -- by creating a mesoscopic interface on the material with a non-superconducting, normal metallic tip where the mesoscopic interface becomes superconducting. Such a phase is now known as a tip-induced superconducting (TISC) phase. This was first seen in 2014 on Cd${}_3$As${}_2$ at IISER Mohali, India. Following that, a large number of other topological materials were shown to display TISC. Since the TISC phase emerges only at a confined region under a mesoscopic point contact, traditional bulk tools for characterizing superconductivity cannot be employed to detect/confirm such a phase. On the other hand, such a point contact geometry is ideal for probing the possible existence of a temperature and magnetic field dependent superconducting energy gap and a temperature and magnetic field dependent critical current. We will review the details of the experimental signatures that can be used to prove the existence of superconductivity even when the "text-book" tests for detecting superconductivity cannot be performed. Then, we will review different systems where a TISC phase could be realized.

References in corpus (91)

• Topological Insulators
• Topological insulators and superconductors
• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Electronic Structure of Pyrochlore Iridates: From Topological Dirac Metal to Mott Insulator
• Discovery of a Weyl Fermion Semimetal and Topological Fermi Arcs
• Discovery of a Three-dimensional Topological Dirac Semimetal, Na3Bi
• Weyl Semimetal in a Topological Insulator Multilayer
• Topological Crystalline Insulators
• Search for Majorana fermions in superconductors
• Topological Materials: Weyl Semimetals
• Dirac semimetal in three dimensions
• Experimental discovery of Weyl semimetal TaAs
• Topological superconductors: a review
• Theoretical Discovery/Prediction: Weyl Semimetal states in the TaAs material (TaAs, NbAs, NbP, TaP) class
• Observation of the chiral anomaly induced negative magneto-resistance in 3D Weyl semi-metal TaAs
• Chern semi-metal and Quantized Anomalous Hall Effect in HgCr2Se4
• Weyl semimetal phase in non-centrosymmetric transition metal monophosphides
• Andreev reflection and Klein tunneling in graphene
• Extremely large magnetoresistance and ultrahigh mobility in the topological Weyl semimetal NbP
• Observation of Weyl nodes in TaAs
• Superconductivity in CuxBi2Se3 and its implications for pairing in the undoped topological insulator
• Introduction to topological superconductivity and Majorana fermions
• Dirac Cone Protected by Non-Symmorphic Symmetry and 3D Dirac Line Node in ZrSiS
• Signatures of the Adler-Bell-Jackiw chiral anomaly in a Weyl Fermion semimetal
• Specular Andreev reflection in graphene
• Topological Crystalline Insulators and Topological Superconductors: From Concepts to Materials
• Topological Superconductivity in CuxBi2Se3
• Dirac Fermions in Solids - from High Tc cuprates and Graphene to Topological Insulators and Weyl Semimetals
• Symmetry and Topology in Superconductors - Odd-frequency pairing and edge states -
• Landau Quantization and Quasiparticle Interference in the Three-Dimensional Dirac Semimetal Cd3As2
• Observation of topological order in a Superconducting doped topological insulator (based on the Bi2Se3 class)
• Experimental discovery of a topological Weyl semimetal state in TaP
• Observation of Topological Nodal Fermion Semimetal Phase in ZrSiS
• Spin-filtered Edge States with an Electrically Tunable Gap in a Two-Dimensional Topological Crystalline Insulator
• Topology of Andreev Bound States with Flat Dispersion
• Observation of Dirac node formation and mass acquisition in a topological crystalline insulator
• Search for Majorana fermions in multiband semiconducting nanowires
• Observation of superconductivity in 3D Dirac semimetal Cd3As2 crystal
• Probing multiband superconductivity by point-contact spectroscopy
• The role of critical current on point contact Andreev Reflection spectrum between a normal metal and a superconductor
• Role of the orbital degree of freedom in iron-based superconductors
• Unconventional Superconductivity at Mesoscopic Point-contacts on the 3-Dimensional Dirac Semi-metal Cd${}_3$As${}_2$
• Topological superconductivity in Dirac semimetals
• Evidence for massive bulk Dirac Fermions in Pb${}_{1-x}$Sn${}_x$Se from Nernst and thermopower experiments
• Giant Anisotropic Magnetoresistance in a Quantum Anomalous Hall Insulator
• Tantalum Monoarsenide: an Exotic Compensated Semimetal
• Electron scattering in tantalum monoarsenide
• Soft Superconducting Gap in Semiconductor Majorana Nanowires
• Dirac mass generation from crystal symmetry breaking on the surfaces of topological crystalline insulators
• Spin polarization and texture of the Fermi arcs in the Weyl Fermion semimetal TaAs
• Tunneling Conductance and Surface States Transition in Superconducting Topological Insulators
• Helical order in one-dimensional magnetic atom chains and possible emergence of Majorana bound states
• Extremely large and significantly anisotropic magnetoresistance in ZrSiS single crystals
• Enhanced superconducting pairing interaction in indium-doped tin telluride
• Directional point-contact Andreev-reflection spectroscopy of Fe-based superconductors: Fermi surface topology, gap symmetry, and electron-boson interaction
• Inducing superconductivity in Weyl semi-metal microstructures by selective ion sputtering
• Unconventional superconductivity in CuxBi2Se3
• Mapping the unconventional orbital texture in topological crystalline insulators
• Fermiology of Strongly Spin-Orbit Coupled Superconductor Sn1-xInxTe and its Implication to Topological Superconductivity
• Transport spin polarisation in SrRuO3 measured through Point Contact Andreev reflection
• Thermoelectric quantum oscillations in ZrSiS
• Andreev spectra and subgap bound states in multiband superconductors
• Quasi-particle interferences of the Weyl semimetals TaAs and NbP
• Mesoscopic superconductivity and high spin polarization coexisting at metallic point contacts on the Weyl semimetal TaAs
• Effects of large induced superconducting gap on semiconductor Majorana nanowires
• Constructing a Weyl semimetal by stacking one dimensional topological phases
• Coexistence of two order parameters and a pseudogaplike feature in the iron-based superconductor LaFeAsO_(1-x)F_x
• Absence of zero-energy surface bound states in CuxBi2Se3 via a study of Andreev reflection spectroscopy
• Pressure induced re-emergence of superconductivity in superconducting topological insulator Sr0.065Bi2Se3
• Higher-Tc superconducting phase in Sr2RuO4 induced by uniaxial pressure
• Theory of magnetotunneling spectroscopy in spin triplet p-wave superconductors
• Conductance spectroscopy of topological superconductor wire junctions
• Surface superconductivity in a three-dimensional Cd${}_3$As${}_2$ semimetal
• Topological superconductivity and Majorana fermions in hybrid structures involving cuprate high-T_c superconductors
• Pure spin-Hall magnetoresistance in Rh/Y3Fe5O12 hybrid
• Possible pressure-induced topological quantum phase transition in the nodal line semimetal ZrSiS
• Proximity-induced superconductivity and Josephson critical current in quantum spin Hall systems
• Unexpected superconductivity at nanoscale junctions made on the topological crystalline insulator Pb${}_{0.6}$Sn${}_{0.4}$Te
• Phase-incoherent superconducting pairs in the normal state of Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Quasi-classical theory of tunneling spectroscopy in superconducting topological insulator
• Doubling of the critical temperature of FeSe observed in point contacts
• Tip-induced Superconductivity Coexisting with Preserved Topological Properties in Line-nodal Semimetal ZrSiS
• Low-energy excitations and non-BCS superconductivity in Nb${}_x$-Bi${}_2$Se${}_3$
• Enhanced superconductivity at the interface of W/Sr${}_2$RuO${}_4$ point contact
• Superconducting proximity effect in semiconductor nanowires
• Undergraduate experiment in point-contact spectroscopy with a Nb/Au junction
• Anisotropic superconductivity in La(O,F)BiSeS crystals revealed by field-angle dependent Andreev reflection spectroscopy
• Disorder-induced subgap states and Majorana zero-energy edge modes in two-dimensional topological insulator-superconductor hybrid structures
• Gap-like feature in the normal state of $\mathbf{X}(\mathbf{F}{\mathbf{e}}_{1-\mathbf{x}}\mathbf{C}{\mathbf{o}}_{\mathbf{x}}{)}_2\mathbf{A}{\mathbf{s}}_2$, $\mathbf{X}=\mathbf{Ba},\mathbf{Sr}$ and $\mathbf{F}{\mathbf{e}}_{1+\mathbf{y}}\mathbf{Te}$ revealed by Point Contact Spectroscopy
• Enhanced zero-bias conductance peak and splitting at mesoscopic interfaces between an $s$-wave superconductor and a 3D Dirac semimetal
• Giant Enhancement of Superconductivity in Zr Point Contacts