Co-Growth of Antiferromagnetic Fe-Intercalated Nb-Based Dichalcogenides with Superconducting Fe(Te,Se) Single Crystals

In recent years, intercalated transition-metal dichalcogenide (ITMD) Fe1/3NbS2 single crystals have attracted significant research attention as a platform for investigating antiferromagnetic (AFM) spintronics. However, its isostructural counterpart Fe1/3NbSe2 has rarely been reported. The primary challenge lies in the difficulty of growing high-concentration FexNbSe2 (x > 0.3) single crystals via the chemical vapor transport (CVT) method, where the actual x is no more than 0.25. This limitation has significantly hindered research on heavily Fe-intercalated NbSe2 systems. Here, we developed an innovative approach using Fe(Te,Se) as a flux to grow high-concentration Fe-intercalated NbSe2 single crystals. By systematically tuning the Te/Se stoichiometric ratio in the starting materials, we identified the optimal crystal-growth condition at Te:Se = 0.6:0.4. This method successfully achieves simultaneous growth of two distinct single crystals, AFM Fe0.35NbSe2 with trace Te doping and superconducting Fe(Te,Se). This work establishes a new pathway for investigating AFM spintronic devices and superconducting quantum materials, while also providing valuable references for growing other high-concentration ITMD single crystals.