Two-dimensional and Disordered Superconductors (TIDES)

Liste des Contributions

9. Experimental aspects of 2D superconductivity and topology

Ding Zhang (Tsinghua University)

08/07/2026 16:00

Superconductivity in highly crystalline 2D materials has become a vibrant field. It not only encompasses emergent quantum phenomena including Ising superconductivity but also helps us deepen the understanding on issues such as quantum phase transitions.

This lecture consists of two parts. In the first part, I will take NbSe2 as an example and review the studies over the decade that are...

36. Perspectives on the Superconductor-Insulator-Transition

Christoph Strunk (University of Regensburg)

09/07/2026 10:00

The interplay of electron-electron interactions and strong disorder superconductor-insulator transition leads to the superconductor-insulator transition (SIT). Beginning with the pioneering experiment of Haviland et al. [1], this phenomenon has remained enigmatic. This begins with the question of what to call an insulator. Very early, scaling theories exploited a duality of Cooper-pairs and...

22. Summer School Lecture 1: Introduction to the Superconductor-Insulator Transition

Mohit Randeria (Ohio State University)

09/07/2026 14:30

This lecture will be a pedagogical introduction to the theory of the disorder-driven superconductor-to-insulator transition in 2D s-wave superconductors, developed over the years with N. Trivedi and collaborators [1-6]. Predictions for and comparisons with experiments will be emphasized. For students who want to do some background reading, I especially recommend reference [3s] and [4].

[1]...

23. Summer School Lecture 2: Are There Bounds on the Superconducting Transition Temperature?

Mohit Randeria (Ohio State University)

10/07/2026 10:00

The question of understanding limits on the superconducting transition temperature Tc is of great fundamental and technological importance. I will begin with a pedagogical introduction to this question and describe recent progress on deriving rigorous upper bounds [1] on the Tc of 2D superconductors applicable to a wide range of quantum materials and to ultracold atomic gases. I will...

7. Quantum critical collapse of the pinned vortex glass at the superconductor-insulator transition

Dr Benjamin SACEPE (Institut Néel, CNRS Grenoble)

13/07/2026 09:30

Superconducting films of amorphous indium oxide (a:InO) undergo a transition to an insulating state upon increasing disorder or magnetic field. The gradual suppression of the critical temperature as the disorder-driven transition is approached has long suggested a continuous collapse of the superfluid density, in line with the conventional picture of a continuous quantum phase transition. In...

37. Origin of the superconductor-insulator transition in disordered two-dimensional films

Christoph Strunk (University of Regensburg)

13/07/2026 10:00

The superconductor-to-insulator transition (SIT) originates from the competition between Anderson localization, which tends to localize single-particle wavefunctions, and superconductivity, which establishes long-range correlations in the superconducting order parameter. The evolution of the sheet resistance and the superfluid stiffness is monitored in a wide range of disorder strength.
We...

24. Conference Talk: On the pairing symmetry of moiré graphene superconductors

Mohit Randeria (Ohio State University)

13/07/2026 10:30

Eight years after the discovery of superconductivity in magic-angle twisted bilayer graphene, its pairing symmetry is not definitively established. I will first discuss existing experimental and theoretical constraints on the SC order parameter. I will then focus on Andreev spectroscopy, which is a phase sensitive probe uniquely suited to address this issue. I will describe recent theoretical...

29. Scanning SQUID View of Quantum Materials

Beena Kalisky (Bar Ilan University)

13/07/2026 11:30

Competition between electronic orders with similar energy scales can give rise to complex emergent behaviors. Detecting traces of such orders requires versatile probes, which access different aspects of the system, such as conductivity, superconductivity and magnetism. I will describe few material systems where scanning SQUID view uncovered surprising mesoscopic effects. Two polymorphs of...

5. Inverse melting of the vortex lattice in a-Re6Zr thin films

Pratap Raychaudhuri (Tata Institute of Fundamental Research, Mumbai)

13/07/2026 12:00

Inverse melting refers to a phenomenon where a liquid transforms into a solid with increase in temperature before melting again at a higher temperature. Predicted more than a century ago, inverse melting is rarely observed. In this talk, I will describe low temperature scanning tunneling spectroscopy experiments on a 20 nm thick amorphous Re6Zr (a-Re6Zr) thin films from which we observe direct...

11. Disordered superconducting nanoporous films – Model systems to explore BKT physics and quantum phase transitions

Sangita Bose (UM-DAE Centre for Excellence in Basic Sciences)

13/07/2026 12:30

Conference Talk

27. Sub-gap modes observed with Kinetic inductance detectors: source of extra-dissipation in disordered thin superconductors?

Florence LEVY-BERTRAND (CNRS - Institut Néel)

14/07/2026 09:30

Kinetic inductance detectors (KIDs) are state-of-the-art detectors used for observations in the millimeter-wave range in astrophysics. They are planar resonant circuits consisting of thin superconducting films deposited on an insulating substrate. The photon detection principe consists in monitoring the shift in the resonance frequency, which is proportional to the incident power [1]....

33. Current bistability in insulators with large localization lengths

Prof. Miguel ORTUÑO (Universidad de Murcia)

14/07/2026 10:30

Beyond a critical disorder, two-dimensional superconductors become insulating at the Superconductor-Insulator Transition (SIT) [1-2]. We present an experimental study on insulating a-YxSi1-x films in the vicinity of the SIT, as well as corresponding numerical simulations of the electrical conductivity [3]. At the lowest temperatures, electronic transport is activated.
On the insulating side,...

41. Controlling magnetic domain walls with supercurrents

Tero Heikkilä (University of Jyväskylä, Finland)

14/07/2026 11:30

Establishing a versatile, fast and reliable magnetic memory technology is a giant bottleneck for cryogenic computing since present-day room-temperature solutions either cease to work or consume too much power. The long-term goal of superconducting spintronics has been to overcome this bottleneck by generating magnetic memories with equal-spin triplet supercurrent driven through them to control...

21. Recombination of localized quasiparticles in an disordered superconductors probed with resonators

Pieter de Visser;de Visser (SRON / TU Delft, Netherlands)

14/07/2026 12:00

Disordered superconductors offer new impedance regimes for quantum circuits, enable a pathway to protected qubits, and can improve superconducting detectors due to their high kinetic inductance and sheet resistance. Our focus is on kinetic inductance detectors for visible- to near-infrared wavelengths, for exoplanet research.
The performance of these devices is determined by quasiparticles...

10. Lithium intercalation induces superconductivity with anomalous metal phase, resistance/gap oscillations, and even ferromagnetism

Ding Zhang (Tsinghua University)

14/07/2026 13:30

Lithium intercalation is a powerful approach to realizing emergent quantum phenomena in a variety of material systems. Here we report our recent studies of lithium intercalated superconductors by utilizing a solid lithium-ion conductor. We transfer exfoliated materials such as TiSe2 [1,2], Bi2Sr2CaCu2O8+x (Bi-2212) [3], and FeSe [4] on this conductor. The exfoliated flakes can be intercalated...

30. Anomalous metal states in cuprate, Fe-based, and nickelate superconducting films

Prof. Jian Wang (Peking University)

14/07/2026 14:00

Governed by the fundamental Heisenberg uncertainty principle, two ground states are expected in two-dimensional (2D) Cooper pair systems: the zero-resistance superconducting state with phase-coherent Cooper pairs and the insulating state with localized Cooper pairs. Whether an intermediate metallic ground state exists in 2D superconducting system has been a long debate.

In the thin films of...

46. From Majorana to Andreev and Back

Ramon AGUADO SOLA (Quantum Advanced Research Center (QuARC) and Institute of Materials Science Madrid (ICMM), Spanish Research Council (CSIC))

15/07/2026 10:00

The promise of Majorana zero modes (MZMs) for fault-tolerant topological quantum computing stems from their unique non-Abelian statistics and inherent topological protection from local decoherence [1]. However, after fifteen years of research, distinguishing MZMs from near-zero-energy Andreev bound states (ABSs) in hybrid devices remains a key challenge. This “Majorana versus Andreev”...

25. Search for spin-triplet superconductivity in van der Waals hybrid systems

Elke Scheer (University of Konstanz)

15/07/2026 11:00

Hybrid structures combining a superconductor (S) with a magnetically inhomogeneous
material (F) are known to generate long-range, spin-polarized (spin-triplet) Cooper pairs
[1]. The magnetic inhomogeneity at S/F interfaces converts singlet and zero-spin-triplet
Cooper pairs into fully polarized spin-triplet Cooper pairs. Experimental support for this
mechanism has been obtained from...

35. Misfit compounds as a platform for engineering topological superconductivity

Tristan Cren (INSP, CNRS - Sorbonne University)

15/07/2026 12:00

In the current quest of innovative materials which combine two-dimensionality, strong spin-orbit, valley physics, superconductivity, charge density waves, quantum-spin Hall effect, the transition metal dichalcogenides (TMD) misfit materials appear as extremely promising. They are constituted by sandwiching rocksalt layers, such as LaSe, and TMD layers such as NbSe$_2$. A very large combination...

47. Gate-tunable Rashba-like edge modes versus quantum spin Hall channels in Bi2Se3 nanoplates

Chuan Li (University of Twente)

15/07/2026 12:30

Feike van Veen1, Jara Vliem2, Femke Witmans3, Daniel Vanmaeckelberg4, Alexander Brinkman1, and Chuan Li1
1 MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
2 Institute of Physical and Theoretical Chemistry, University of T¨ubingen, D-72076 T¨ubingen, Germany
3 II. Physikalisches Institut, Universit¨at zu Koln, D-50937 Koln, Germany and
4 Debye...

28. Tunnelling spectroscopy of few-monolayer NbSe2: possible magnetism, and nonequilibirum effects

Charis Quay (Université Paris-Saclay), Jericho Narvasa (Laboratoire de Physique des Solides (Universite Paris-Saclay))

16/07/2026 10:00

Superconducting transition metal dichalcogenides in the few- and monolayer limit, such
as NbSe2, can sustain high in-plane magnetic fields, due to their Ising (or valley Zeeman)
spin-orbit coupling (ISOC), which pins the internal spin axis of Cooper pairs out-of-plane. The
interplay of the Ising field and the in-plane magnetic field has been predicted to give rise to
non-conventional...

17. Layer-selective Cooper pairing in an alternately stacked transition metal dichalcogenide

Miguel Ugeda (Donostia International Physics Center (DIPC))

16/07/2026 10:30

Materials exhibiting multiple superconducting phases are exceptionally rare in nature. The few known examples of multiphase superconductors display complex phase diagrams, where distinct phases can be independently induced by means of external stimuli such as pressure or magnetic fields. Here we report the coexistence of two superconducting condensates with different spatial localization in...

13. Unveiling Novel Aspects of Superconductivity in Twisted Trilayer Graphene

Mitali Banerjee (Ecole Polytechnique Federal de Lausanne)

16/07/2026 11:30

Twisted trilayer graphene (TTG) has emerged as a particularly intriguing platform for studying moiré superconductivity. Its flat-band physics closely resembles that of twisted bilayer graphene, yet TTG offers an additional degree of tunability in its band structure, providing a valuable handle for uncovering the mechanisms of moiré superconductivity. In addition, the interference between the...

32. Upper critical field and pairing symmetry in 2D Ising superconducting materials

Dr Lena Engstrom

16/07/2026 12:00

Lena Engström1*, Ludovica Zullo2, Tristan Cren3, Andrej Mesaros1, Pascal Simon1
1 Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
2 Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden, Universität Würzburg, 97074 Würzburg, Germany
3Sorbonne Université, CNRS, Institut des Nanosciences de Paris, UMR7588, F-75252 Paris,...

18. Controlling topological superconducting phases in TMD heterostructure

Dganit MEIDAN (SPMS/CentraleSupelec)

16/07/2026 12:30

Transition metal dichalcogenides (TMDs) offer a highly tunable platform for investigating topological phases and unconventional superconductivity. In this talk, I will focus on hexagonally structured monolayers, where the heavy transition metal and the broken inversion symmetry give rise to Ising spin orbit coupling. I will begin by discussing a topological nodal superconducting phase...

8. Pressure Induced Anomalous Metal in the Vicinity of the Superconductor Insulator Transition

Dr Roy Cohen (Bar Ilan university)

17/07/2026 09:30

The Superconductor-to-Insulator Transition (SIT) in two-dimensional superconductors occurs due to a competition between superconductivity, quantum interferences, Coulomb interactions, and disorder. Despite extensive theoretical and experimental investigation, the SIT remains an active research area due to the potential for exotic phases near the transition. One such phase is the Anomalous...

20. Percolation and (super)conduction: 2d superconductors with correlated disorder

Giulia Venditti

17/07/2026 10:00

Two-dimensional superconductors should exhibit a Berezinskii–Kosterlitz–Thouless (BKT) transition, and the 𝑇-dependence of the superfluid stiffness should distinguish between nodal or gapped order parameter symmetries. However, this picture dramatically changes when large scale inhomogeneities and spatially correlated disorder are taken into account, washing out BKT signatures. At the same...

40. Bulk Localized Collective Excitations in Strongly Disordered Superconductors

Anton KHVALYUK (Laboratoire de Physique de l'ENS de Lyon, CNRS)

17/07/2026 10:30

Macroscopic electromagnetic response of a superconductor is described by a finite superfluid stiffness $\theta$, which underlies hallmark phenomena such as dissipationless current flow. In conventional superconductors, these properties persist at finite temperature $T$ and frequency $\omega$ due to a hard superconducting gap. The conventional Mattis‑Bardeen framework further predicts that...

48. AC Josephson effect in graphene for quantum metrology

Nicolas Aparicio Da Silva (LNE)

17/07/2026 11:00

Quantum electrical standards in the International System of units (SI) are challenging to put in practice together as their working conditions are nowadays intrinsically incompatible. The magnetic field required to realize the quantum Hall effect for the primary resistance standard prevents superconductivity, which is at the core of the quantum voltage standard through the AC Josephson effect....

6. Absolute measurement of penetration depth of superconducting thin films using microwave stripline resonators

Pratap Raychaudhuri (Tata Institute of Fundamental Research, Mumbai)

Superconducting microstrip resonators, which leverage kinetic inductance to probe electrodynamics, are sensitive tools for studying superconducting thin films at microwave frequencies. However, extracting the absolute superconducting penetration depth, from these measurements remains challenging. In this work, we present a hybrid method to determine the absolute value of over a wide...

15. Dielectric properties of NbN-films at the insulating side of the superconductor-insulator-transition

Max Reinhart (University of Regensburg)

In 2D strongly disordered thin films the superconductor-insulator-transition (SIT) occurs [1]. The resistive behaviour of the insulating side of this transition is well studied, as it has been observed in various materials [2,3]. For the imaginary part of the impedance the situation is less clear. While it is known, that the superconducting side behaves inductive, we performed experiments on...

19. Disordered superconductivity in boron-doped nanocrystalline diamond

Georgina Klemencic (University of Glasgow)

Boron-doped nanocrystalline diamond (BNCD) is a low-temperature granular superconductor with typical transition temperatures of order 3-5 K and upper critical fields of several tesla [1,2]. The superconductivity develops within a columnar, microstructured material whose superconducting properties are strongly dependent on growth conditions [2-4]. Microwave measurements also show a large sheet...

16. Emergence of gapless superconductivity in annealed molybdenum nitride thin films

Frederik Bolle (University of Stuttgart)

Molybdenum nitride (MoN) is a disordered superconductor, which garnered attention due to its high critical temperature ($\delta$-MoN: $T_c\sim 13\,\text{K}$), robustness in high magnetic fields and short coherence lengths, which allows the deposition of ultra-thin films below 5 nm, a property that is crucial for superconducting detector applications.
Here we report on another interesting...

38. Finite-size effects in the vicinity of the BKT transition in superconducting NbN thin films

Christoph Strunk (Uni Regensburg)

For 2D superconducting thin films, Halperin and Nelson predicted a finite resistance above the Berezinskii-Kosterlitz-Thouless temperature TBKT caused by the unbinding of thermally excited vortex-antivortex pairs. Recently, we observed a sharp BKT-transition in homogeneously disordered 3nm NbN films grown by ALD, which is in very good agreement with these theoretical predictions [1]. Although...

44. Imaging phase information in the hybrid Josephson junction array

Beena Kalisky (Bar Ilan University)

Many superconducting systems behave as Josephson-junction arrays (JJAs), either intrinsically or via disorder-induced weak links near the critical temperature. Artificial JJAs suppress disorder, making them an optimal model system for various condensed matter states, such as the superconductor-insulator transition. Since phase coherence is the dominant factor in JJAs, it is crucial to develop...

34. Light induced control of the superconducting state in infinite-layer nickelates

Florian Giletta

Experiments on illuminated high-Tc cuprate superconductors (HTS) have revealed that their ground state can be manipulated by photo-induced effects [1]. However, the mechanism underlying both superconductivity and these photo-induced phenomena in HTS remain elusive. An alternative route to better understand the origins of HTS consists in studying analogous systems, such as the recently...

2. Microwave kinetic inductance and phase fluctuation of disordered and granular superconductors

Jan Pusskeiler (1. Physikalisches Institut, University of Stuttgart)

Kinetic inductance $L_\mathrm{kin}$ quantifies the inertia of the superconducting condensate and hence the low-temperature electrodynamics of superconducting microwave circuitry. We directly probe the inductive response in the broadband reactance of superconducting granular aluminum and titanium nitride from MHz to GHz frequencies, $\mathrm{Im}(𝑍) = \omega \cdot L_\mathrm{kin}$, by Corbino...

39. Mixed-order phase transitions driven by two types of interactions in a single disordered superconducting network

Yuval Sallem (Bar-Ilan university, department of physics)

Mixed-order phase transitions, which combine abrupt phase switching with critical behavior, are uncommon in condensed-matter systems. Here, we demonstrate a mixed-order normal metal to superconductor transition in a single two-dimensional disordered superconducting network, driven by the interplay of two types of interactions: local electrical connectivity and long-range thermally mediated...

26. Non-equilibrium quasiparticle dynamics in disordered superconductors after absorption of single photons

Steven de Rooij;de Rooij (Leiden University)

Increasing disorder in a superconductor increases the kinetic inductance. This enables high impedance quantum circuits and sensitive single photon detectors with a high absorption efficiency. These applications are susceptible to quasiparticle excitations. The single photon response in microwave kinetic inductance detectors (MKIDs) is dictated by quasiparticle recombination, and quasiparticles...

43. Scanning SQUID view of quantum materials

Nadav Rothem (Bar Ilan University)

Our group develops and uses SQUID-based magnetic imaging to study quantum materials and exotic states of matter. The strengths of this technique lie in its ability to locally map the behavior of electrons in real space. For example, to probe unconventional superconductors we simultaneously map the spatial distribution of the superfluid density, magnetic signals and induced normal- and...

14. Superconductivity in Ni–Bi Bilayer Thin Films: Evidence for Anisotropic Strong-Coupling Pairing

Sulagna Dutta (Tata Institute of Fundamental Research, Mumbai)

We report superconductivity in sputter-deposited Ni–Bi bilayer thin films with varying thicknesses [Bi (40–80 nm)/Ni (5–10 nm)]. While as-deposited films show no superconductivity, post-deposition annealing induces the formation of the intermetallic NiBi3 phase, leading to the emergence of superconductivity. The Bi (80 nm)/Ni (10 nm) film, corresponding closely to NiBi₃ stoichiometry, exhibits...

12. The nature of the “pseudogap” in the insulating phase of highly disordered superconductors

Aviad Frydman (Bar Ilan University, Israel)

Disordered thin films undergoing a superconductor–insulator transition provide a controlled setting for studying pseudogap physics in the absence of competing electronic orders. Although theory predicts that local Cooper pairing can survive deep into the insulating phase, direct spectroscopic confirmation has remained experimentally inaccessible because tunneling measurements in highly...

42. Topological phase transitions induced by structural disorder in amorphous Chern insulators

Andrii Syrota (Laboratoire de physique des Solides)

Topological phases of matter exhibit robust conducting edge states tied to invariants such as the Chern number. While well understood in crystalline systems due to presence of symmetries, their realization in disordered or amorphous materials remains less explored.
Here we study the evolution of a decorated honeycomb crystalline lattice to a hyperuniform amorphous system by introducing...

31. Ultra-slow dynamics in out-of-equilibrium superconductors

Mathis RAY (IJCLab)

The behavior of superconducting materials in a magnetic field is well known (Meissner effect, Abrikosov vortices for instance). However, one might wonder how super-currents behave when they coexist with an electric field. The London theory predicts infinite velocity of the charge carriers, which is unphysical. This is a challenging problem of out-of-equilibrium behavior.
To observe this...

45. What Can Disordered Semiconductors Teach Us About The 2D Superconductor- Insulator Transition?

Jonathan Gough

Electrical transport on the insulating side of the two-dimensional superconductor-insulator transition (2DSIT) remains nontrivial. Unlike conventional disordered insulators, which exhibit Mott’s variable-range hopping (VRH), insulating films near the 2DSIT display simple activated transport at low temperatures, an activation energy that increases below a characteristic temperature and a...