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arXiv · 1606.01667

Tracking local magnetic dynamics via high-energy charge excitations in a relativistic Mott insulator

Nicola Nembrini·Simone Peli·Francesco Banfi·Gabriele Ferrini·Yogesh Singh·Philipp Gegenwart·Riccardo Comin·Kateryna Foyevtsova·Andrea Damascelli·Adolfo Avella·Claudio Giannetti
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Abstract

We use time- and energy-resolved optical spectroscopy to investigate the coupling of electron-hole excitations to the magnetic environment in the relativistic Mott insulator Na$_2$IrO$_3$. We show that, on the picosecond timescale, the photoinjected electron-hole pairs delocalize on the hexagons of the Ir lattice via the formation of quasi-molecular orbital (QMO) excitations and the exchange of energy with the short-range-ordered zig-zag magnetic background. The possibility of mapping the magnetic dynamics, which is characterized by typical frequencies in the THz range, onto high-energy (1-2 eV) charge excitations provides a new platform to investigate, and possibly control, the dynamics of magnetic interactions in correlated materials with strong spin-orbit coupling, even in the presence of complex magnetic phases.

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Nicola Nembrini, Simone Peli, Francesco Banfi, Gabriele Ferrini, Yogesh Singh, Philipp Gegenwart, Riccardo Comin, Kateryna Foyevtsova, Andrea Damascelli, Adolfo Avella, Claudio Giannetti. 2016-06-06. Tracking local magnetic dynamics via high-energy charge excitations in a relativistic Mott insulator. https://doi.org/10.1103/physrevb.94.201119

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