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arXiv · 2007.14662

Ultrafast spin-nematic and ferroelectric phase transitions induced by femto-second light pulses

Sangeeta Rajpurohit·Liang Z. Tan·Christian Jooss·P. E. Blöchl
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Abstract

Optically-induced phase transitions of the manganite $\rm Pr_{1/3}Ca_{2/3}MnO_3$ have been simulated using a model Hamiltonian, that captures the dynamics of strongly correlated charge, orbital, lattice, and spin degrees of freedom. Its parameters have been extracted from first-principles calculations. Beyond a critical intensity of a femto-second light pulse, the material undergoes ultra-fast and non-thermal magnetic phase transition from a non-collinear to collinear antiferromagnetic phases. The light-pulse excites selectively either a spin-nematic or a ferroelectric phase depending on the light-polarization. The behavior can be traced to an optically induced ferromagnetic coupling between Mn-trimers, i.e. polarons which are delocalized over three Mn-sites. The polarization guides the polymerization of the polaronic crystal into distinct patterns of ferromagnetic chains determining the target phase.

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Sangeeta Rajpurohit, Liang Z. Tan, Christian Jooss, P. E. Blöchl. 2020-11-28. Ultrafast spin-nematic and ferroelectric phase transitions induced by femto-second light pulses. https://doi.org/10.1103/physrevb.102.174430

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