Broadband Infrared Spectrometer

• Subject Area: Condensed Matter Physics
• Term: Funded in 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 432733812

Optical spectroscopy is one of the key experimental techniques used in the chair of Experimental Physics V and employed in many ongoing and planned research projects. Prominent examples are the first detection of the generic excitations of multiferroics, namely the electromagnons and the magnetoelectric spin-wave excitations, the discovery of universalities in the exchange-induced phonon splitting at antiferromagnetic transitions, or the identification of Bethe strings by THz spectroscopy in high magnetic fields. However, the currently used spectrometers are more than 20 years old and no longer correspond to the state-of-the-art in infrared and THz spectroscopy. Moreover, they are becoming increasingly unreliable, there is no further service and maintenance provided by their manufacturer, and their computer control is only possible with outdated system software and hardware. Thus a soon end of the product lifetimes of these two devices can be clearly foreseen. The new spectrometer requested in the present proposal has considerably enhanced experimental capabilities, promoting further advances in the research performed by our group. It is essential for the continuation of our very successful investigations using optical spectroscopy, e.g., within the Transregio TRR80 and the Priority Program SPP 2137 and prerequisite for the realization of various planned projects, described in the proposal. Especially, the new spectrometer will play a crucial role in the investigation of magnon modes in multiferroics and complex magnets, for the study of dynamic magnetoelectric effects and the corresponding optical-diode function in multiferroic and magnetoelectric materials, and for the observation of antiferromagnetic and magnetoelectric domains. In addition, it will be applied for the exploration of exotic excitations in quantum magnets, for the study of the polar dynamics in non-canonical ferroelectrics, and for the detection of magnetic-order driven structural changes in spin-charge-lattice coupled systems. Further fields of application of this device are the investigation of structural distortions in skyrmion-host materials (e.g., lacunar spinels) via changes in their lattice dynamics and in their electronic band structure, the examination of the topological band structures in Dirac materials, and the investigation of fast dynamics in glassy matter. Besides the excellent spectral resolution and bandwidth of the new spectrometer, all these studies will profit from the broadband optical micro-spectroscopy and the Raman options only included in the new setup. The optical cryostat with a built-in superconducting magnet will be crucial to perform such spectroscopic studies on magnetic compounds, which are the materials in the focus of our interest.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Breitband Infrarot-Spektrometer
• Instrumentation Group: 1830 Fourier-Transform-IR-Spektrometer
• Applicant Institution: Universität Augsburg
• Leader: Professor Dr. István Kézsmárki