Energy-Resolved Ultrafast Spectroscopic Investigation on the Spin-Coupled Electronic States in Multiferroic Hexagonal HoMnO(3)

A complete temperature-dependent scheme of the Mn(3+) on-site d-d transitions in multiferroic hexagonal HoMnO(3) (h-HoMnO(3)) thin films was unveiled by energy-resolved ultrafast spectroscopy. The results unambiguously revealed that the ultrafast responses of the e(1g) and e(2g) states differed significantly in the hexagonal HoMnO(3). We demonstrated that the short-range antiferromagnetic and ferroelectric orderings are more relevant to the e(2g) state, whereas the long-range antiferromagnetic ordering is intimately coupled to both the e(2g) and e(1g) states. Moreover, the primary thermalization times of the e(2g) and e(1g) states were 0.34 ± 0.08 ps and 0.38 ± 0.08 ps, respectively.