Thermodynamic parameters of atomically thin superconductors derived from the upper critical field

Abstract

The amplitude of ground state superconducting energy gap $\Delta (0)$ and relative jump in electronic specific heat at the transition temperature, $\Delta$$C$$/$$\gamma$$T_c$, are primary fundamental parameters of any superconductor. There are several well-established techniques to measure these values for bulk samples. However, there is limited number of techniques which can be applied to measure these parameters in atomically thin superconductors. Here we proposed a new approach to extract $\Delta (0)$ and $\Delta$$C$$/$$\gamma$$T_c$ in atomically thin superconductors by utilizing perpendicular, Bc2,perp(T) (when magnetic field is applied in perpendicular direction to the film surface), and parallel, Bc2,||(T) (when magnetic field is applied in parallel direction to the film surface), upper critical field data. Deduced parameters for few layers thick Al, Sn, NbSe2, MoS2, magic angle twisted trilayer graphene (MATTG), and WTe2 are well matched values expected for strong- and moderately strong-coupled electron-phonon mediated superconductors. Observed, in many atomically thin superconductors, an enhancement of Bc2,||(0) above the Pauli-Clogston-Chandrasekhar limiting field (i.e., magnetic field required to break the Cooper pair) is explained based on the sample geometry, without an assumption that some exotic pairing mechanism, for instance, Ising-type, is emergent in these materials.

arXiv comment32 pages, 9 figures, 1 table

References in corpus (34)

• Magic-angle graphene superlattices: a new platform for unconventional superconductivity
• Evidence of Ising pairing in superconducting NbSe${}_2$ atomic layers
• Two Dimensional Ising Superconductivity in Gated MoS${}_2$
• Tunable Phase Boundaries and Ultra-Strong Coupling Superconductivity in Mirror Symmetric Magic-Angle Trilayer Graphene
• Superconductivity protected by spin-valley locking in ion-gated MoS2
• Highly crystalline 2D superconductors
• Superconductivity in rhombohedral trilayer graphene
• Tuning Ising superconductivity with layer and spin-orbit coupling in two-dimensional transition-metal dichalcogenides
• Electrically Tunable Low Density Superconductivity in a Monolayer Topological Insulator
• Gate-induced Superconductivity in atomically thin MoS2 crystals
• Gate-induced superconductivity in a monolayer topological insulator
• Superconductivity at 253 K in lanthanum-yttrium ternary hydrides
• Field-reentrant superconductivity close to a metamagnetic transition in the heavy-fermion superconductor UTe${}_2$
• Universal self-field critical current for thin-film superconductors
• Type-II Ising Pairing in Few-Layer Stanene
• Momentum-resolved superconducting gap in the bulk of Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$ from combined ARPES and $\mu$SR measurements
• Superconducting Phase-Diagram of H3S under High Magnetic Fields
• Two-dimensional Superconductors with Atomic-scale Thicknesses
• Transport evidence of asymmetric spin-orbit coupling in few$-$layer superconducting 1Td$-$MoTe${}_2$
• Pauli-limiting effects in the upper critical fields of a clean LiFeAs single crystal
• Type-II Ising superconductivity and anomalous metallic state in macro-size ambient-stable ultrathin crystalline films
• Energy gap measurement of nanostructured thin aluminium films for use in single Cooper-pair devices
• Superconductivity at 6 K and the violation of Pauli limit in Ta2PdxS5
• On the origin of critical temperature enhancement in atomically-thin superconductors
• Suppression of superconductivity and enhanced critical field anisotropy in thin flakes of FeSe
• Superconductivity emerging from a stripe charge order in IrTe2 nanoflakes
• Superconductivity with High Upper Critical Field in the Cubic Centrosymmetric $\eta$-Carbide Nb${}_4$Rh${}_2$C${}_{1-\delta }$
• NbIr${}_2$B${}_2$ and TaIr${}_2$B${}_2$ -- new low symmetry noncentrosymmetric superconductors with strong spin orbit coupling
• Classifying superconductivity in an infinite-layer nickelate Nd${}_{0.8}$Sr${}_{0.2}$NiO${}_2$
• Group-9 Transition Metal Suboxides Adopting the Filled-Ti${}_2$Ni Structure: A Class of Superconductors Exhibiting Exceptionally High Upper Critical Fields
• Unusual evolution of B_{c2} and T_c with inclined fields in restacked TaS_2 nanosheets
• Evidence of fully-gapped superconductivity in NbReSi: A combined $\mu$SR and NMR study
• An approach to 1000 T using the Electro-Magnetic Flux Compression
• Unusual Resistive Transitions in the Nodal-Line Semimetallic Superconductor NaAlSi

Cited by in corpus (1)

• The compliance of the upper critical field in magic-angle multilayer graphene with the Pauli limit