Non-collinear spin states in bottom-up fabricated atomic chains

Abstract

Non-collinear spin states with unique rotational sense, such as chiral spin-spirals, are recently heavily investigated because of advantages for future applications in spintronics and information technology and as potential hosts for Majorana Fermions when coupled to a superconductor. Tuning the properties of such spin states, e.g., the rotational period and sense, is a highly desirable yet difficult task. Here, we experimentally demonstrate the bottom-up assembly of a spin-spiral derived from a chain of iron atoms on a platinum substrate using the magnetic tip of a scanning tunneling microscope as a tool. We show that the spin-spiral is induced by the interplay of the Heisenberg and Dzyaloshinskii-Moriya components of the Ruderman-Kittel-Kasuya-Yosida interaction between the iron atoms. The relative strengths and signs of these two components can be adjusted by the interatomic iron distance, which enables tailoring of the rotational period and sense of the spin-spiral.

Majorana fermions in magnetic chains

“…[63,64,65]. We also note that such spin helices have been indeed observed in other 1D-atomic system by STM measurements [66,67,68,69]. variations in single molecules within ∼ 0.05Å precision [73,74].…”

Atom-by-atom construction of attractors in a tunable finite size spin array

“…Moreover, as we show, the multi-well regime can be utilized to create stable attractors in spin-based hardware, serving as a platform for associative memory and recurrent neural networks. Experimentally, atoms on surfaces which exhibit strong RKKY interactions serve as a viable platform to test the theoretical proposals outlined in this study [33][34][35][36][37][38]. In the case that an individual spin exhibits strong uniaxial out of plane anisotropy, at sufficiently low temperature, the system can be reduced to a treatment of the lowest doublet, i.e.…”

“…We note that in experiments, the RKKY interaction deviates from the isotropic model [33,35,38]; however we do not see indications that this changes the primary conclusions labeled here for the isotropic case. Likewise, it would be interesting to probe the energy landscapes for systems beyond this limit, namely to probe spins in an easy plane configuration [40], or in the limit where chiral magnetic interactions are significant [33,37]. AAK acknowledges funding from NWO, and the VIDI project: 'Manipulating the interplay between superconductivity and chiral magnetism at the single-atom level' with project number 680-47-534.…”

Long range of indirect exchange interaction on the edges of MoS2flakes

“…The non-collinear DyaloshinskiiMoriya interaction is seen to gradually rise with separation, reaching an amplitude comparable to the Ising component after a separation of nearly ten lattice constants. All this behavior would suggest probing the tunable interaction between impurities near the edges of such TMD flakes, which would further result in stable helical structures for many-impurity assemblies which could be examined by local probes, such as spinpolarized STM [49,50,51]. Given the electronic and structural similarity of several TMDs, stable and well defined phases in these systems may open the door to interesting spintronic applications in these versatile material systems.…”

“…As the Fermi level and impurity separation may be tunable via doping and manipulation, respectively, these systems may provide interesting new playground to explore the behavior of 1D magnetic ensembles. Although such helical structures have been recently shown controllable in metallic systems [49,50,51], our predictions on TMDs would have interesting advantages, since several TMDs have similar band gaps, large SOC strengths, and welldefined crystallite edges, suggesting the exploration of long-range interaction would be supported by stable and accessible structures, less susceptible to quantum or thermal fluctuations.…”