Direct observation of the superconducting gap in thin film of titanium nitride using terahertz spectroscopy

Abstract

We report on the charge carrier dynamics of superconducting titanium nitride (TiN) in the frequency range 90 - 510 GHz (3 - 17 cm-1). The experiments were perfomed on a 18 nm thick TiN film with a critical temperature of 3.4 K. Measurements were carried out from room temperature down to 2 K, and in magnetic fields up to 7 T. We extract the real and imaginary parts of the complex conductivity as a function of frequency and temperature, directly providing the superconducting energy gap. Further analysis yields the superconducting London penetration depth. The findings as well as the normal state properties strongly suggest conventional BCS superconductivity, underlined by the BCS ratio 3.44. Detailed analysis of the charge carrier dynamics of the silicon substrate is also discussed.

arXiv comment5 pages, 7 figures, RevTex 4.1, Phys. Rev. B accepted manuscript

References in corpus (11)

• Disorder-Induced Inhomogeneities of the Superconducting State Close to the Superconductor-Insulator Transition
• Fractal superconductivity near localization threshold
• Localized Superconductivity in the Quantum-Critical Region of the Disorder-Driven Superconductor-Insulator Transition in TiN Thin Films
• Single and two-particle energy gaps across the disorder-driven superconductor-insulator transition
• Pseudogap in a thin film of a conventional superconductor
• Superconducting phase transitions in ultrathin TiN films
• A dynamical study of phase fluctuations and their critical slowing down in amorphous superconducting films
• Theory of Magneto-resistance of Disordered Superconducting Films
• Identifying capacitive and inductive loss in lumped element superconducting hybrid titanium nitride/aluminum resonators
• Optical Properties of TiN Thin Films close to the Superconductor-Insulator Transition
• Terahertz conductivity of the heavy-fermion compound UNi2Al3

Cited by in corpus (21)

• The Higgs Mode in Disordered Superconductors Close to a Quantum Phase Transition
• Atomic layer deposition of titanium nitride for quantum circuits
• A flexible design platform for Si/SiGe exchange-only qubits with low disorder
• Electrodynamics of the Superconducting State in Ultra-Thin Films at THz Frequencies
• A superconducting switch actuated by injection of high energy electrons
• Electrodynamic response and local tunnelling spectroscopy of strongly disordered superconducting TiN films
• On the Role of Out-of-Equilibrium Phonons in Gated Superconducting Switches
• Optical signatures of the superconducting Goldstone mode in granular aluminum: experiments and theory
• Superconducting Energy Scales and Anomalous Dissipative Conductivity in Thin Films of Molybdenum Nitride
• Maglev for Dark Matter: Dark-photon and axion dark matter sensing with levitated superconductors
• Complete electrodynamics of a BCS superconductor with $\mu$eV energy scales: microwave spectroscopy on titanium at mK temperatures
• Microwave study of superconducting Sn films above and below percolation
• A Robust nitridation technique for fabrication of disordered superconducting TiN thin films featuring phase slip events
• Ultrahigh-inductance materials from spinodal decomposition
• Superconducting Levitated Detector of Gravitational Waves
• Random telegraph fluctuations in granular microwave resonators
• Semiconductor Epitaxy in Superconducting Templates
• Pairing Fluctuation AC Conductivity of Disordered Thin Films
• The effect of superconducting fluctuations on the ac conductivity of a 2D electron system in the diffusive regime
• Development of TiN/AlN-based superconducting qubit components
• Beyond Homes scaling: disorder, the Planckian bound and a new universality