Spin multifunctional transport properties of C ₁₃ and C ₁₄ molecule-based molecular nanodevices

Cyclocarbon molecules are promising candidates for molecular spintronics because they are newly synthesized carbon allotropes with excellent physical and chemical characteristics. Sun <i>et al.</i> (<i>Nature</i>, 2023, <b>623</b>, 972-976) synthesized C₁₄ on an anthracene surface <i>via</i> tip-induced dehalogenation ring-opening reactions, demonstrating superior thermodynamic stability compared to C₁₈. Albrecht <i>et al.</i> (<i>Science</i>, 2024, <b>384</b>, 677-682) utilized scanning probe microscopy tip manipulation to synthesize C₁₃<i>in situ</i> on decachlorofluorene, revealing a triplet ground state and a twisted geometric structure. This study utilizes first-principles calculations to explore the spin-multifunctional transport properties of nanodevices comprising C₁₃ and C₁₄ molecules that are connected in a coplanar manner to a zigzag-edged graphene nanoribbon. All considered devices exhibit spin filtering effects and rectification characteristics in parallel and antiparallel spin states. The spin filtering efficiency almost approaches 99% across the entire bias range, and the maximum rectification ratio exceeds 1 × 10⁴ for both C₁₃ and C₁₄ systems. Besides, the C₁₄ device displays considerable negative differential resistance, achieving a maximum peak-to-valley ratio of 5.71. Furthermore, modulating the temperature and thermal gradient of the nanoribbon electrodes enables thermal spin filtering, with thermal spin filtering efficiency in the parallel state approaching 99%. These findings provide theoretical guidance for designing multifunctional spin nanodevices based on cyclocarbon molecules, highlighting their potential as candidate materials for carbon-based device applications.