Momentum-resolved electronic band structure and offsets in an epitaxial NbN/GaN superconductor/semiconductor heterojunction

Abstract

The electronic structure of heterointerfaces play a pivotal role in their device functionality. Recently, highly crystalline ultrathin films of superconducting NbN have been integrated by molecular beam epitaxy with the semiconducting GaN. We use soft X-ray angle-resolved photoelectron spectroscopy to directly measure the momentum-resolved electronic band structures for both NbN and GaN constituents of this Schottky heterointerface, and determine their momentum-dependent interfacial band offset as well as the band-bending profile into GaN. We find, in particular, that the Fermi states in NbN are aligned against the band gap in GaN, which excludes any significant electronic cross-talk of the superconducting states in NbN through the interface to GaN. We support the experimental findings with first-principles calculations for bulk NbN and GaN. The Schottky barrier height obtained from photoemission is corroborated by electronic transport and optical measurements. The momentum-resolved understanding of electronic properties elucidated by the combined materials advances and experimental methods in our work opens up new possibilities in systems where interfacial states play a defining role.

References in corpus (14)

• Angle-resolved photoemission spectroscopy of the cuprate superconductors
• Interfacial mode coupling as the origin of the enhancement of Tc in FeSe films on SrTiO3
• Phonon-enhanced superconductivity at the FeSe/SrTiO3 interface
• Polaronic metal state at the LaAlO3/SrTiO3 interface
• Origin of the crossover from polarons to Fermi liquids in transition metal oxides
• The New Nitrides: Layered, Ferroelectric, Magnetic, Metallic and Superconducting Nitrides to Boost the GaN Photonics and Electronics Eco-System
• Unveiling the superconducting mechanism of Ba${}_{0.51}$K${}_{0.49}$BiO${}_3$
• k-Space imaging of anisotropic 2D electron gas in GaN/GaAlN high-electron-mobility transistor heterostructures
• Computational Framework for Angle-Resolved Photoemission Spectroscopy
• Epitaxial niobium nitride superconducting nanowire single-photon detectors
• Three-dimensional Fermi surface of 2H-NbSe${}_2$ - Implications for the mechanism of charge density waves
• Do topology and ferromagnetism cooperate at the EuS/Bi${}_2$Se${}_3$ interface?
• Visualizing dispersive features in 2D image via minimum gradient method
• Isotropic Kink and Quasiparticle Excitations in the Three-Dimensional Perovskite Manganite La${}_{0.6}$Sr${}_{0.4}$MnO${}_3$

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