732 citations · 3.4k across the 45 of their papers we have counts for
46 papers
Superconductivity from interband coupling to ferroelectric quantum critical fluctuations in two dimensions
Sudip Kumar Saha, Jonathan Ruhman, Avraham Klein
Soft critical fluctuations associated with ferroelectric quantum phase transitions are typically transverse owing to their polar nature. This implies that the conventional density-…
Competing incommensurability, electronic correlations, and superconductivity in a hybrid transition metal dichalcogenide
Jean C. Souza, Moshe Haim, Lorenzo Crippa +8
The engineering of superlattices in two-dimensional van der Waals materials has enabled the realization of rich phase diagrams hosting topological and strongly correlated phases. W…
Reduced pair breaking from extended disorder in unconventional superconductors: implications to 4Hb-TaS
Yuval Tsur, Mark H. Fischer, Jonathan Ruhman
Unconventional superconductivity is generally expected to be strongly suppressed by nonmagnetic disorder, as captured by Abrikosov--Gor'kov (AG) theory. However, several materials,…
Interlayer Charge-Transfer Ferroelectric Fluctuations as a Pairing Mechanism in van der Waals Superconductors
Ankan Biswas, Jagannath Sutradhar, Sudip Kumar Saha +2
Signatures of unconventional superconductivity have been reported in a wide range of van der Waals (vdW) materials. However, their microscopic origin remains unclear due to competi…
Mixed Triplet-Singlet Order Parameter in Decoupled Superconducting 1H Monolayers of Transition-Metal Dichalcogenides
Avior Almoalem, Sajilesh Kunhiparambath, Roni Anna Gofman +9
Understanding the emergence of unconventional superconductivity, where the order parameter deviates from simple isotropic s-wave pairing, is a central puzzle in condensed matter ph…
Comment on 2501.17230 and 2502.00103 "Phonon-mediated electron attraction in SrTiO3 via the generalized Frohlich and deformation potential mechanisms" and "Theory of ab initio downfolding with arbitrary range electron-phonon coupling"
Jonathan Ruhman
This comment critically examines the claims made in arXiv papers arXiv:2501.17230 and arXiv:2502.00103, which argue that a multiplicity of polar optical phonons can generate a long…
Strong Coupling Theory of Superconductivity and Ferroelectric Quantum Criticality in metallic SrTiO
Sudip Kumar Saha, Maria N. Gastiasoro, Jonathan Ruhman +1
Superconductivity in doped SrTiO has remained an enduring mystery for over 50 years. The material's status as a ``quantum" ferroelectric metal, characterized by a soft polar mo…
The Smearing of Quasi-Particles: Signatures in the Entanglement Entropy of Excited Many-Particle Systems
Jagannath Sutradhar, Jonathan Ruhman, Avraham Klein +2
The entanglement spectrum serves as a powerful tool for probing the structure and dynamics of quantum many-body systems, revealing key information about symmetry, topology, and exc…
Flat band physics in the charge-density wave state of -TaS
Amir Dalal, Jonathan Ruhman, Jörn W. F. Venderbos
1-TaS is the only insulating transition-metal dichalcogenide (TMD) with an odd number of electrons per unit cell. This insulating state is non-magnetic, making it a potentia…
The transition-metal-dichalcogenide family as a superconductor tuned by charge density wave strength
Shahar Simon, Hennadii Yerzhakov, Sajilesh K. P. +6
Metallic transition metal dichalcogenides (TMDs), consisting of H-NbSe, H-NbS, H-TaSe and H-TaS, remain superconducting down to a thickness of a single layer. In th…
Singlet, triplet, and mixed all-to-all pairing states emerging from incoherent fermions
Jagannath Sutradhar, Jonathan Ruhman, Avraham Klein
The electron-electron and electron-phonon coupling in complex materials can be more complicated than simple density-density interactions, involving intertwined dynamics of spin, ch…
The field theory of a superconductor with repulsion
Amir Dalal, Jonathan Ruhman, Vladyslav Kozii
A superconductor emerges as a condensate of electron pairs, which bind despite their strong Coulomb repulsion. Eliashberg's theory elucidates the mechanisms enabling them to overco…
A mechanism for phase shifts in Little-Parks experiments: application to 4Hb-TaS and to 2H-TaS intercalated with chiral molecules
Mark H. Fischer, Patrick A. Lee, Jonathan Ruhman
Recently, unusual phase shifts in Little-Parks experiments performed on two systems derived from the layered superconductor 2H-TaS were reported. These systems share the co…
A theory of criticality for quantum ferroelectric metals
Avraham Klein, Vladyslav Kozii, Jonathan Ruhman +1
A variety of compounds, for example doped paraelectrics and polar metals, exhibit both ferroelectricity and correlated electronic phenomena such as low-density superconductivity an…
Evidence of a two-component order parameter in 4Hb-TaS2 in the Little-Parks effect
Avior Almoalem, Irena Feldman, Michael Shlafman +5
Finding unambiguous evidence of non-trivial pairing states is one of the greatest experimental challenges in the field of unconventional superconductivity. Such evidence requires p…
Magnetic memory and spontaneous vortices in a van der Waals superconductor
Eylon Persky, Anders V. Bjørlig, Irena Feldman +7
Doped Mott insulators exhibit some of the most intriguing quantum phases of matter, including quantum spin-liquids, unconventional superconductors, and non-Fermi liquid metals. Suc…
Majorana-Weyl cones in ferroelectric superconductors
Hennadii Yerzhakov, Roni Ilan, Efrat Shimshoni +1
Topological superconductors are predicted to exhibit outstanding phenomena, including non-abelian anyon excitations, heat-carrying edge states, and topological nodes in the Bogoliu…
Synergetic ferroelectricity and superconductivity in zero-density Dirac semimetals near quantum criticality
Vladyslav Kozii, Avraham Klein, Rafael M. Fernandes +1
We study superconductivity in a three-dimensional zero-density Dirac semimetal in proximity to a ferroelectric quantum critical point. We find that the interplay of criticality, in…
Robust Gapless Superconductivity in 4Hb-TaS
David Dentelski, Ezra Day-Roberts, Turan Birol +2
The superconducting TMD 4Hb-TaS consists of alternating layers of H and T structures, which in their bulk form are metallic and Mott-insulating, respectively. Recently, this co…
Non-universal current flow near the metal-insulator transition in an oxide interface
Eylon Persky, Naor Vardi, Ana Mafalda R. V. L. Monteiro +9
In systems near phase transitions, macroscopic properties often follow algebraic scaling laws, determined by the dimensionality and the underlying symmetries of the system. The eme…
The Orbitally Selective Mott Phase in Electron Doped Twisted TMDs: A Possible Realization of the Kondo Lattice Model
Amir Dalal, Jonathan Ruhman
Moiré super-potentials in two-dimensional materials allow unprecedented control of the ratio between kinetic and interaction energy. By this, they pave the way to study a wide vari…
Measurement and entanglement phase transitions in all-to-all quantum circuits, on quantum trees, and in Landau-Ginsburg theory
Adam Nahum, Sthitadhi Roy, Brian Skinner +1
A quantum many-body system whose dynamics includes local measurements at a nonzero rate can be in distinct dynamical phases, with differing entanglement properties. We introduce th…
Pairing in magic-angle twisted bilayer graphene: role of phonon and plasmon umklapp
Cyprian Lewandowski, Debanjan Chowdhury, Jonathan Ruhman
Identifying the microscopic mechanism for superconductivity in magic-angle twisted bilayer graphene (MATBG) is an outstanding open problem. While MATBG exhibits a rich phase-diagra…
The effect of interorbital scattering on superconductivity in doped Dirac materials
David Dentelski, Vladyslav Kozii, Jonathan Ruhman
Unconventional superconductivity has been discovered in a variety of doped materials, including topological insulators, semimetals and twisted bilayers. A unifying property of thes…