腾讯会议：315-399-300 ，密码：7413

报告摘要：

Quantum materials display a wide range of interesting dynamical phenomena, from soft phonon modes to spin and charge excitations, and the study of dynamical properties can yield profound insight into the physics of these systems. Many important types of excitations couple to light, and can thus be investigated using optical spectroscopy. Yet the relevant energy scales in several prominent material systems are in the meV range, where optical spectroscopy becomes challenging. The most commonly used experimental approach is time-domain THz spectroscopy, a powerful technique that has been extensively used in studies of quantum materials. Yet time-domain measurements are typically limited to energies above ~1 meV, and are difficult to perform in materials with high reflection coefficients. In this talk, I will describe a novel approach to infrared spectroscopy at sub-THz frequencies developed in my group [1], that enables sensitive optical absorption measurements in highly reflecting samples down to 0.2 meV. The technique bridges the gap between microwave spectroscopy and established time-domain methods, and enables experiments that probe both charge and spin degrees of freedom. I will discuss several examples: our recent observation of spin-phonon hybridized modes in metallic strontium titanate [2], measurements of antiferromagnetic resonance in layered van der Waals magnetic systems [3], and studies of the low-energy optical response in candidate topological superconductors based on SnTe. 

[1] L. Rogić et al., Rev. Sci. Instrum. 96, 083101 (2025)
[2] N. Somun et al., arxiv:2606.03908 (2026)
[3] J. J. Abraham et al., Adv. Funct. Mater. 36, e11057 (2026)

报告人简介：

Dr. Damjan Pelc obtained his PhD from the University of Zagreb, Croatia, in 2017, and spent three years as a postdoctoral researcher at the University of Minnesota in the group of Prof. Martin Greven. He is now Associate Professor at the University of Zagreb, where he leads a group with focus on experimental condensed matter physics. His interests are in the field of quantum materials, primarily unconventional superconductivity in complex oxides and layered materials, as well as exotic magnetism and quantum spin liquid phases. His group uses a combination of experimental approaches, including neutron and x-ray scattering, optical spectroscopy, and magnetic resonance, and is actively engaged in the development of new techniques.

邀请人 ：罗军 副研究员

联系人：魏佳 secuf_wj@iphy.ac.cn