Extended Data Fig. 2: Exchange couplings involved in the goblet chain system.
From: Tunable topological phases in nanographene-based spin-1/2 alternating-exchange Heisenberg chains
a, Topographic image of a modified mirror-symmetric dimer containing only the nearest inter-goblet coupling Jinter. Vbias = 100 mV, Iset = 500 pA. The dI/dV spectra taken at different spin sites are displayed in the right panel (Iset = 500 pA), with the averaged d2I/dV 2 spectrum represented as a light brown curve. b, Topographic image of a modified dimer containing only the second nearest inter-goblet coupling Jnn. Vbias = − 50 mV, Iset = 500 pA. The dI/dV spectra taken at different spin sites are displayed in the right panel (Iset = 500 pA). c, Topographic image of a modified dimer containing only the third nearest inter-goblet coupling Jnnn. Vbias = − 50 mV, Iset = 500 pA. The dI/dV spectra taken at various spin sites are displayed in the right panel (Iset = 800 pA). d, Topographic image of an engineered dimer containing Jintra, Jnn, and Jnnn. Vbias = − 50 mV, Iset = 300 pA. The corresponding dI/dV spectra are also shown in the right panel, with the averaged d2I/dV 2 spectrum of 3 and 4 represented as a light brown curve. All white scale bars denote 0.5 nm. The background spectra taken on the Au(111) substrate are shown as references. All dI/dV spectra are taken with Vrms = 2 mV.
