Microscopic design of a synthetic spin-1 chain in an InAsP quantum dot array

We present here the steps enabling the microscopic design of a synthetic spin-1 chain in an InAsP quantum dot (QD) array embedded in an InP nanowire. The chain is described by a two-leg multiorbital Hubbard Kanamori (HK) model with parameters obtained from the microscopic calculations of up to eight electrons in a single and double QD. In this HK model describing long arrays of QDs, using both exact diagonalization and matrix product state (MPS) tools, we demonstrate a fourfold quasidegenerate ground state separated from excited states by a finite energy gap similar to a Heisenberg spin-1 chain in the Haldane phase. We demonstrate characteristic behavior of spin-1/2 quasiparticles at the edges of the chain by observing the magnetic field dependence of the low-energy spectrum as a function of the applied magnetic field. The applied magnetic field isolates the singlet and Sᶻ=0 triplet states from the other triplet components emulating a singlet-triplet qubit but with macroscopic quantum states. Most importantly, the regions in parameter space where the low-energy spectrum of the multiorbital Hubbard chain yields a Heisenberg spin-1 chain spectrum are mapped out.