Extreme In-Plane Upper Critical Magnetic Fields of Heavily Doped Quasi 2D Transition Metal Dichalcogenides -- Misfit $(LaSe)_{1.14}(NbSe_2)_{n=1,2}$

1 INSP-E2 - Spectroscopie des nouveaux états quantiques
INSP - Institut des Nanosciences de Paris
7 LaTEQS - Laboratoire de Transport Electronique Quantique et Supraconductivité
PHELIQS - PHotonique, ELectronique et Ingénierie QuantiqueS : DRF/IRIG/PHELIQS
Abstract : Extreme in-plane upper critical magnetic fields $B_{c2//ab}$ strongly violating the Pauli paramagnetic limit have been observed in the misfit layer $(LaSe)_{1.14}(NbSe_2)$ and $(LaSe)_{1.14}(NbSe_2)_2$ single crystals with $T_c$ = 1.23 K and 5.7 K, respectively. The crystals show a 2D-3D transition at the temperatures slightly below $T_c$ with an upturn in the temperature dependence of $B_{c2//ab}$, a temperature dependent huge superconducting anisotropy and a cusp-like behavior of the angular dependence of $B_{c2}$. As shown in our previous work a strong charge transfer occurs in $(LaSe)_{1.14}(NbSe_2)_2$ which makes this compound behaving as a stack of highly doped $NbSe_2$ monolayers, where the strong upper critical field can be attributed to the Ising coupling recently discovered in atomically thin transition metal dichalcogenides with strong spin-orbit coupling and lack of inversion symmetry. Surprisingly, while showing a very similar behavior $(LaSe)_{1.14}(NbSe_2)$ seems to imply a very different mechanism not related to Ising coupling since superconductivity rather appears in the $LaSe$ layers while $NbSe_2$ layers behave like tunneling barriers. Despite their fundamental differences a common denominator in both misfits is a strong charge transfer from $LaSe$ to $NbSe_2$ that makes them behaving as a stack of almost decoupled superconducting atomic layers.
Document type :
Preprints, Working Papers, ...

https://hal.archives-ouvertes.fr/hal-03431208
Contributor : Tristan Cren Connect in order to contact the contributor
Submitted on : Tuesday, November 16, 2021 - 3:27:22 PM
Last modification on : Wednesday, April 27, 2022 - 3:58:54 AM

Identifiers

• HAL Id : hal-03431208, version 1
• ARXIV : 2107.07302

Citation

Tristan Cren, P. Samuely, P. Szabó, J. Kačmarčík, A. Meerchaut, et al.. Extreme In-Plane Upper Critical Magnetic Fields of Heavily Doped Quasi 2D Transition Metal Dichalcogenides -- Misfit $(LaSe)_{1.14}(NbSe_2)_{n=1,2}$. 2021. ⟨hal-03431208⟩

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