Robust Quantum Griffiths Singularity at above 1.5 Kelvin in Nitride Thin Films

Abstract

Quantum Griffiths singularity (QGS), which is closely correlated with the quenched disorder, is characterized by the divergence of the dynamical critical exponent and the presence of activated scaling behavior. Typically such a quantum phenomenon is rather rare and only observed in extremely low temperatures. Here we report the experimental observation of a robust QGS in nitride thin films, NbN, which survives in a rather high temperature range. The electrical transport propertied were measured under the magnetic field up to 12 T. The field induced superconductor-metal transitions were observed with the continuously changed transition points with the decrease of temperature. The dynamical critical exponent based on the conventional power-law scaling reveals a divergent trend when approaching the the low temperature limit. Moreover, the temperature and field dependence of sheet resistance can be described by the activated scaling analysis in the temperature region up to 1.6 K $\le T\le$ 4.0 K. We argue that the robustness of QGS in the present system originates from the Pauli paramagnetic effect due to the strong coupling between the magnetic field and the spin degree of freedom.

arXiv comment6 pages, 4 figures

References in corpus (14)

• Continuous Quantum Phase Transitions
• Strong disorder RG approach of random systems
• Ising Superconductivity and Quantum Phase Transition in Macro-Size Monolayer NbSe2
• Quantum Griffiths effects and smeared phase transitions in metals: theory and experiment
• Thickness-Magnetic Field Phase Diagram at the Superconductor-Insulator Transition in 2D
• Theory of quantum metal to superconductor transitions in highly conducting systems
• Renormalization group study of the two-dimensional random transverse-field Ising model
• Quantum phase transitions in highly crystalline two-dimensional superconductors
• Electric-Field Induced Superconductor-Insulator Transitions in Exfoliated Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ Flakes
• Observation of Quantum Griffiths Singularity and Ferromagnetism at Superconducting LaAlO3/SrTiO3(110) Interface
• The observation of in-plane quantum Griffiths singularity in two-dimensional crystalline superconductors
• Dynamical conductivity at the dirty superconductor-metal quantum phase transition
• Infinite-randomness fixed point of the quantum superconductor-metal transitions in amorphous thin films
• Investigation of the Pauli paramagnetic effect in systematically tuned NbN thin films

Cited by in corpus (4)

• Three-dimensional quantum Griffiths singularity in bulk iron-pnictide superconductors
• Direct evidence for two-gap superconductivity in hydrogen-intercalated titanium diselenide
• Quantum Griffiths singularity in three-dimensional MoTiN superconducting films
• Influences of $N_2$ flow rate on the superconducting properties and dimensionality of epitaxial TiN thin films