Zusammenfassung
Spin chains in solid state materials are quintessential quantum systems with potentialapplications in spin-based logic, memory, quantum communication, and computation.A critical challenge is the experimental determination of spin lifetimes with the ultimategoal of increasing it. Local measurements by scanning tunneling microscopy (STM)have demonstrated the importance of decoupling spins from their environment, withmarkedly improved lifetimes in spin chains on the surfaces of band insulators. In thiswork we use low-temperature scanning tunneling microscopy to reveal long-lifetimeexcitations in a chain of spin-1/2 electrons embedded in a charge density wave Mottinsulator, 1T-TaS2. Naturally occurring domain walls trap chains of localized spin-1/2electrons in nearby sites, whose energies lie inside the Mott gap. Spin-polarized meas-urements on these sites show distinct two-level switching noise, as well as negative dif-ferential resistance in thedI/dVspectra, typically associated with spinfluctuations. Theexcitations show exceptionally long lifetimes of a few seconds at 300 mK. Our worksuggests that layered Mott insulators in the chalcogenide family, which are amenable toexfoliation and lithography, may provide a viable platform for quantum applications.
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