2017/02/28 by Kok Wee Song, A. E. Koshelev, Alexei E. Koshelev · 1 citation
Materials Science · Physics and Astronomy · #Condensed matter physics #Iron-based superconductors research #Landau quantization #Magnetic field #Pairing #Phase (matter) #Phase diagram #Physics #Physics of Superconductivity and Magnetism #Quantization (signal processing) #Quantum mechanics #Superconductivity #Superconductivity in MgB2 and Alloys #Zeeman effect #Zeeman energy #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.95.174503
published as Phys. Rev. B 95, 174503 (2017) · 23 pages, 9 figures, more references added and one figure added
arxiv created 2017/04/06 · openalex publication_date 2017/05/04 · arxiv updated 2017/05/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We investigate the onset of superconductivity in a magnetic field for a clean two-dimensional multiple-band superconductor in the vicinity of the Lifshitz transition when one of the bands is very shallow. Due to the small number of carriers in this band, the quasiclassical Werthamer-Helfand approximation breaks down and Landau quantization has to be taken into account. We found that the transition temperature TC2(H) has giant oscillations and is resonantly enhanced at the magnetic fields corresponding to the matching of the chemical potential with the Landau levels in the shallow band. This enhancement is especially pronounced for the lowest Landau level. As a consequence, the reentrant superconducting regions in the temperature-field phase diagram emerge at low temperatures near the magnetic fields at which the shallow-band Landau levels cross the chemical potential. The specific behavior depends on the relative strength of the intraband and interband pairing interactions and the reentrance is most pronounced in the purely interband coupling scenario. The reentrant behavior is suppressed by the Zeeman spin splitting in the shallow band; the separated regions disappear already for very small spin-splitting factors. On the other hand, the reentrance is restored in the resonance cases when the spin-splitting energy exactly matches the separation between the Landau levels. The predicted behavior may be realized in the gate-tuned FeSe monolayer.