Superconducting Sn-Intercalated TaSe${}_2$: Structural Diversity Obscured by Routine Characterization Techniques

Abstract

Using Sn-intercalated TaSe${}_2$ as a model system, we demonstrate the presence of structural heterogeneity captured by single-crystal X-ray diffraction (SCXRD) and scanning transmission electron microscopy (STEM) that eludes the routine characterization techniques of powder X-ray diffraction, Raman spectroscopy, and electronic transport measurements. From a single growth composition (1:1:2 Sn:Ta:Se), we obtained crystals diverse in stoichiometry and structure, with near-continuous intercalation for Sn${}_x$TaSe${}_2$ from $0\lesssim x\lesssim 1$. Using SCXRD, we found global structural diversity, identifying three new structure types: Sn${}_{0.18}$TaSe${}_{2.0}$/Sn${}_{0.08}$TaSe${}_{1.96}$ ($R3m$), Sn${}_{0.16}$TaSe${}_{2.0}$ ($P{6}_3/mmc$), and Sn${}_{1.2}$TaSe${}_{1.9}$ ($Fmm2$). Using STEM, we observed local structural diversity, manifested as regions of highly variable stacking within a single crystal. In contrast, powder X-ray diffraction did not resolve all observed global structures. Raman spectroscopy was unable to distinguish between different structures or compositions in the standard measurement range. Electronic transport measurements showed consistent superconductivity and charge density wave behavior irrespective of Sn-intercalation amount. Our results indicate that routine approaches to characterization of intercalated transition metal dichalcogenides may be inadequate for capturing the diversity of this family of materials, highlighting the need for high-resolution structural characterization when examining the properties of van der Waals-layered compounds.

References in corpus (24)

• Superconductivity in Cu_xTiSe_2
• Unusual competition of superconductivity and charge-density-wave state in a compressed topological kagome metal
• Superconducting Topological Surface States in Non-centrosymmetric Bulk Superconductor PbTaSe2
• Superconductivity in potassium-doped metallic polymorphs of MoS2
• Enhanced Superconductivity and Suppression of Charge-density Wave Order in 2H-TaS${}_2$ in the Two-dimensional Limit
• Raman Signatures of Polytypism in Molybdenum Disulfide
• Electrical switching in a magnetically intercalated transition metal dichalcogenide
• Polytypism, polymorphism and superconductivity in TaSe2-xTex
• Topological Dirac States and Pairing Correlations in the Non-Centrosymmetric Superconductor PbTaSe2
• Competition between charge-density-wave and superconductivity in the kagome metal RbV3Sb5
• Polar and phase domain walls with conducting interfacial states in a Weyl semimetal MoTe2
• Two-Dimensional TaSe2 Metallic Crystals: Spin-Orbit Scattering Length and Breakdown Current Density
• Suppression of charge density wave order by disorder in Pd-intercalated ErTe${}_3$
• Stacking domains in graphene on silicon carbide: a pathway for intercalation
• Evidence of a coupled electron-phonon liquid in NbGe${}_2$
• Correlation between crystal purity and the charge density wave in 1$T$-VSe${}_2$
• Striped electronic phases in an incommensurately modulated van der Waals superlattice
• Consequences and control of multi-scale (dis)order in chiral magnetic textures
• Tuning Superconductivity and Charge Density Wave Order in 2H-TaSe2 by Modulating the Van Hove Singularity
• Superconductivity in tantalum self-intercalated 4$Ha$-Ta${}_{1.03}$Se${}_2$
• Enhanced Superconductivity in 2H-TaS2 Devices Through in-situ Molecular Intercalation
• Efficient Soft-Chemical Synthesis of Large van-der-Waals Crystals of the Room-Temperature Ferromagnet 1T-CrTe2
• Structural Modulation and Enhanced Magnetic Ordering in Incommensurate K${}_{1-x}$CrSe${}_2$ Crystals
• Non-Wigner-Dyson level statistics and fractal wavefunction of disordered Weyl semimetals