Novel Emergent Phases in a Two-Dimensional Superconductor

Abstract

In this letter, we report our observation of an extraordinarily rich phase diagram of a LaScO${}_3$/SrTiO${}_3$ heterostructure. Close to the superconducting transition temperature, the system hosts a superconducting critical point of the Infinite-randomness type characterized by an effective dynamical exponent $\nu z$ that diverges logarithmically. At lower temperatures, we find the emergence of a magnetic field-tuned metallic phase that co-exists with a quantum Griffiths phase (QGP). Our study reveals a previously unobserved phenomenon in 2D superconductors -- an unanticipated suppression of the QGP below a crossover temperature in this system. This concealment is accompanied by the destruction of the superconducting quantum critical point signaled by a power-law divergence (in temperature) of the effective dynamical exponent. These observations are entirely at odds with the predictions of the infinite-randomness scenario and challenge the very concept of a vanishing energy scale associated with a quantum critical point. We develop and discuss possible scenarios like smearing of the phase transition that could plausibly explain our observations. Our findings challenge the notion that QGP is the ultimate ground state in two-dimensional superconductors.

15 pages, 5 figures, Supplementary Material follows main manuscript

References in corpus (36)

• Strong quantum computational advantage using a superconducting quantum processor
• Quantum information processing with superconducting circuits: a review
• Rare region effects at classical, quantum, and non-equilibrium phase transitions
• Nature of the superconductor-insulator transition in disordered superconductors
• Inhomogeneous Pairing in Highly Disordered s-wave Superconductors
• Metallic ground state in an ion-gated two-dimensional superconductor
• Ising Superconductivity and Quantum Phase Transition in Macro-Size Monolayer NbSe2
• Anomalous metals -- failed superconductors
• Single and two-particle energy gaps across the disorder-driven superconductor-insulator transition
• Disorder-induced rounding of certain quantum phase transitions
• Infinite-randomness critical point in the two-dimensional disordered contact process
• Quantum Griffiths Phase in the weak itinerant ferromagnetic alloy Ni${}_{1-x}$V${}_x$
• Quantum Griffiths effects in itinerant Heisenberg magnets
• Disorder in quantum many-body systems
• Effects of dissipation on a quantum critical point with disorder
• Infinite-randomness quantum critical points induced by dissipation
• Extreme Sensitivity of the Superconducting State in Thin Films
• Two-stage magnetic-field-tuned superconductor-insulator transition in underdoped La${}_{2-x}$Sr${}_x$CuO${}_4$
• Theory of smeared quantum phase transitions
• Electric-Field Induced Superconductor-Insulator Transitions in Exfoliated Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ Flakes
• Type-II Ising superconductivity and anomalous metallic state in macro-size ambient-stable ultrathin crystalline films
• Superconductivity from repulsive interaction
• Observation of Quantum Griffiths Singularity and Ferromagnetism at Superconducting LaAlO3/SrTiO3(110) Interface
• Absence of conventional quantum phase transitions in itinerant systems with disorder
• Two-dimensional superconductor-insulator quantum phase transitions in an electron-doped cuprate
• Quantum Griffiths phase inside the ferromagnetic phase of Ni${}_{1-x}$V${}_x$
• Dynamical Conductivity Across The Disorder-Tuned Superconductor-Insulator Transition
• Phases and phase transitions in disordered quantum systems
• Extrinsic and Intrinsic Anomalous Metallic States in Transition Metal Dichalcogenide Ising Superconductors
• Infinite-randomness fixed point of the quantum superconductor-metal transitions in amorphous thin films
• Dynamical conductivity at the dirty superconductor-metal quantum phase transition
• Anomalous quantum metal in a 2D crystalline superconductor with intrinsic electronic non-uniformity
• Dissipation effects in random transverse-field Ising chains
• Signatures of a Quantum Griffiths Phase close to an Electronic Nematic Quantum Phase Transition
• Charge Dynamics Across the Disorder Driven Superconductor-Insulator Transition
• Observation of transient superconductivity at the LaAlO${}_3$/SrTiO${}_3$ interface

Cited by in corpus (1)

• Smeared phase transition in the dissipative random quantum Ashkin-Teller model