title: Polar Dynamics at the Jahn-Teller Transition in Ferroelectric GaV₄S₈.
abstract: We present a dielectric spectroscopy study of the polar dynamics linked to the orbitally driven ferroelectric transition in the Skyrmion host GaV(4)S(8). By combining THz and MHz-GHz spectroscopy techniques, we succeed in detecting the relaxational dynamics arising from coupled orbital and polar fluctuations in this material and trace its temperature dependence in the paraelectric as well as in the ferroelectric phase. The relaxation time significantly increases when approaching the critical temperature from both sides of the transition. It is natural to assume that these polar fluctuations map the orbital dynamics at the Jahn-Teller transition. Because of the first-order character of the orbital-ordering transition, the relaxation time shows an enormous jump of about 5 orders of magnitude at the polar and structural phase transition.
authors.affiliation: Experimental Physics V, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Experimental Physics V, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Ruff
authors.affiliation: Experimental Physics V, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Schmidt
authors.affiliation: Experimental Physics V, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany.|Institute of Applied Physics, Academy of Sciences of Moldova, Chisinau MD-2028, Republic of Moldova.
authors.forename: V
authors.initials: V
authors.lastname: Tsurkan
authors.affiliation: Department of Physics, Budapest University of Technology and Economics, 1111 Budapest, Hungary.|MTA-BME Lendület Magneto-optical Spectroscopy Research Group, 1111 Budapest, Hungary.
authors.forename: I
authors.initials: I
authors.lastname: Kézsmárki
authors.affiliation: Experimental Physics V, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Lunkenheimer
authors.affiliation: Experimental Physics V, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Loidl