Field-induced resistance peak in a superconducting niobium thin film proximity coupled to a surface reconstructed SrTiO3

Abstract

Oxygen vacancy is known to play an important role for the physical properties in SrTiO3(STO)-based systems. On the surface, rich structural reconstructions had been reported owing to the oxygen vacancies, giving rise to metallic surface states and unusual surface phonon modes. More recently, an intriguing phenomenon of a huge superconducting transition temperature enhancement was discovered in a monolayer FeSe on STO substrate, where the surface reconstructed STO (SR-STO) may play a role. In this work, SR-STO substrates were prepared via thermal annealing in ultra-high vacuum followed by low energy electron diffraction analyses on surface structures. Thin Nb films with different thicknesses (d) were then deposited on the SR-STO. The detailed studies of the magnetotransport and superconducting property in the Al(1 nm)/Nb(d)/SR-STO samples revealed a large positive magnetoresistance and a pronounced resistance peak near the onset of the resistive superconducting transition in the presence of an in-plane field. Remarkably, the amplitude of the resistance peak increases with increasing fields, reaching a value of nearly 57% of the normal state resistance at 9 T. Such resistance peaks were absent in the control samples of Al(1 nm)/Nb(d)/STO and Al(1 nm)/Nb(d)/SiO2. Combining with DFT calculations for SR-STO, we attribute the resistance peak to the interface resistance from the proximity coupling of the superconducting niobium to the field-enhanced long-range magnetic order in SR-STO that arises from the spin-polarized in-gap states due to oxygen vacancies.

High-sensitivity of initial SrO growth on the residual resistivity in epitaxial thin films of SrRuO$$_3$$ on SrTiO$$_3$$ (001)

“…We grew all the films under a similar ozone environment and within the adsorption-controlled growth regime. Hence, the significant change in RRR and (5 K) with respect to the is not likely due to either the oxygen vacancy in STO 40 or SRO stoichiometry. To further clarify the oxygen vacancy issue, we post-annealed a sample at 400 C for 8 h under 1 atm O flow, where no noticeable change in the RRR and (5 K) was observed due to post-annealing.…”

Carrier‐Modulated Anomalous Electron Transport in Electrolyte‐Gated SrTiO3

“…[ 47,48 ] The details of discussion on this possible scenario would not be presented here, which is beyond the scope of this work. For the present STO–electrolyte configuration, the Ti 3 d conduction band, surface reconstruction, [ 49 ] and defects‐induced consequences may be all non‐negligible or so. [ 46 ] These sensitivities and consequences can be essentially illustrated in the complex phase diagram, and one updated one is drawn in Figure in more or less semiquantitative sense.…”

High‐Performance GdNiO3Epitaxial Film Memristor for Neuralactivity Analysis

“…[21,22] However, I-RRAM is usually based on interfacial barrier modulation caused by the migration of ions and ion defects such as oxygen ions and vacancies. [23][24][25][26][27][28] It has no electroforming process and will not produce the problems of high variation and low yield caused by electroforming. [29] Through this mechanism, I-RRAM can exhibit stable analog resistance switching (RS) behavior during SET and RESET transitions, enabling more continuous and controllable conductance changes.…”