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Confinement-Deconfinement Transition As An Indication Of Spin-Liquid-Type Behavior In Na2Iro3, Zhanybek Alpichshev, Fahad Mahmood, Gang Cao, Nuh Gedik

Physics and Astronomy Faculty Publications

We use ultrafast optical spectroscopy to observe binding of charged single-particle excitations (SE) in the magnetically frustrated Mott insulator Na₂IrO₃. Above the antiferromagnetic ordering temperature (T_N) the system response is due to both Hubbard excitons (HE) and their constituent unpaired SE. The SE response becomes strongly suppressed immediately below T_N. We argue that this increase in binding energy is due to a unique interplay between the frustrated Kitaev and the weak Heisenberg-type ordering term in the Hamiltonian, mediating an effective interaction between the spin-singlet SE. This interaction grows with distance causing …