Terahertz Spectra Revealing the Collective Excitation Mode in Charge‐Density‐Wave Single Crystal LuFe2O4. Issue 9 (15th August 2017)

• Record Type: Journal Article
• Authors: Liu, Xiumei; Jin, Zuanming; Cheng, Zhenxiang; Lin, Xian; Balakrishnan, Geetha; Ma, Guohong
• Is Part Of: Physica status solidi. Volume 11:Issue 9(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-08-15
• Subjects: charge density wave -- multiferroics -- time‐domain terahertz spectroscopy; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.201700177
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : A low‐energy collective excitation mode in charge‐ordered multiferroic LuFe2 O4 is reported via terahertz time‐domain spectroscopy. Upon cooling from 300 to 40 K, the central resonance frequency showed a pronounced hardening from 0.85 to 1.15 THz. In analogy to the well‐known low‐energy optical properties of LuFe2 O4, this emerging resonance was attributed to the charge–density–wave (CDW) collective excitations. By using the Drude–Lorentz model fitting, the CDW collective mode becomes increasingly damped with the increasing temperature. Furthermore, the kinks of the CDW collective mode at the magnetic transition temperature are analyzed, which indicate the coupling of spin order with electric polarization. Abstract : In this study, the dielectric response of spin‐ and charge‐ordered multiferroic LuFe2 O4 crystal in the terahertz range is investigated. It is shown that a low energy excitation appears below TCO and shifts to higher frequency with narrower bandwidth below T N, which is assigned to the charge‐density‐wave collective mode. The magnetoelectric coupling in LuFe2 O4 is also discussed.