Charge Orders in Fully Intercalated Bilayer TaSe: Dependence on Interlayer Stacking and Intercalation Sites
arXiv:2502.11204 · doi:10.1103/PhysRevB.111.205437
Abstract
Recent advancements have established self-intercalation as a powerful technique for manipulating quantum material properties, with precisely controllable intercalation concentrations. Given the inherently rich phase diagrams of transition metal dichalcogenides (TMDCs), studying the self-intercalated TMDCs can offer promising candidates for investigating the interplay between various orderings. This work focuses on fully intercalated bilayer TaSe (TaSe), which has recently been fabricated experimentally. By performing first-principles calculations, we demonstrate the suppression of an intrinsic charge density wave (CDW) in parent TaSe layers, and the emergence of , , or the absence of a CDW in the intercalated layers, depending on the interlayer stacking orders and intercalation sites being occupied. Particularly, the CDW shows an increase in electronic states at the Fermi level compared to its non-CDW phase. This unusual behavior contrasts with that of typical CDW materials in TMDCs. Furthermore, superconductivity is preserved in these TaSe structures, with superconducting transition temperatures comparable to or substantially smaller than those of TaSe. Spin-orbit coupling is found to enhance the density of states at Fermi levels while simultaneously reducing the electron-phonon coupling matrix elements. These two competing effects result in varying impacts on superconductivity across different TaSe structures. Moreover, our calculations indicate that magnetic order is absent. Our study deepens the understanding of underlying physics in TaSe, and provides experimentally feasible candidates for studying CDW, superconductivity, and their interplay.
10 pages, 7 figures
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