Second-order nonlinear optical and linear UV-VIS absorption properties of type-II multiferroic candidates RbFe(AO4)2 (A = Mo, Se, S)
Abstract
Motivated by the search for type-II multiferroics, we present a comprehensive optical study of a complex oxide family of type-II multiferroic candidates: RbFe(MoO4)2, RbFe(SeO4)2, and RbFe(SO4)2. We employ rotational-anisotropy second harmonic generation spectroscopy (RA SHG), a technique sensitive to point symmetries, to address discrepancies in literature-assigned point/space groups and to identify the correct crystal structures. At room temperature we find that our RA SHG patterns rotate away from the crystal axes in RbFe(AO4)2 (A = Se, S), which identifies the lack of mirror symmetry and in-plane two-fold rotational symmetry. Also, the SHG efficiency of RbFe(SeO4)2 is two orders of magnitude stronger than RbFe(AO4)2 (A = Mo, S), which suggests broken inversion symmetry. Additionally, we present temperature-dependent linear optical characterizations near the band edge of this family of materials using ultraviolet-visible (UV-VIS) absorption spectroscopy. Included is experimental evidence of the band gap energy and band gap transition type for this family. Previously unreported sub-band gap absorption is also presented, which reveals prominent optical transitions, some with an unusual central energy temperature dependence. Furthermore, we find that by substituting the A-site in RbFe(AO4)2 (A = Mo, Se, S), the aforementioned transitions are spectrally tunable. Finally, we discuss the potential origin and impact of these tunable transitions.
Keywords
Cite
@article{arxiv.2008.06950,
title = {Second-order nonlinear optical and linear UV-VIS absorption properties of type-II multiferroic candidates RbFe(AO4)2 (A = Mo, Se, S)},
author = {Rachel Owen and Elizabeth Drueke and Charlotte Albunio and Austin Kaczmarek and Wencan Jin and Dimuthu Obeysekera and Sang-Wook Cheong and Junjie Yang and Steven Cundiff and Liuyan Zhao},
journal= {arXiv preprint arXiv:2008.06950},
year = {2021}
}
Comments
22 pages total: 12 pages of main text, 3 pages of appendix, 1 page of references, 6 pages of figures. 7 figures total: 4 figures in the main body, 3 figures in the appendix. All figure and figure captions are listed at the end of the manuscript