arXiv subjects

M. Tepie

Publications and source records attributed to M. Tepie.

2 recordsLinked to original sources

arXiv2026

Electronic layer decoupling driven by density-wave order in La$_4$Ni$_3$O$_{10}$

We probe the density-wave transition of the trilayer nickelate La$_4$Ni$_3$O$_{10}$ with polarization-resolved infrared spectroscopy. The low-energy electrodynamics is strongly anisotropic, with metallic in-plane and insulating out-of-plane character. In the ordered phase, the anisotropy grows more than an order of magnitude as the out-of-plane conductivity is sharply suppressed. We interpret this enhancement as an effective electronic decoupling of the Ni-O layers, driven by a spin-density-wave-induced redistribution of Ni-$d_{z^2}$ occupation within the trilayers. This electronic response is accompanied by clear shifts and splittings of the out-of-plane phonons, compatible with a density-wave instability of electronic origin.

cond-mat.str-el↗

arXiv2025

Photoinduced Frustration Modulation in $\kappa$-type Quantum Spin Liquid Candidates

Geometric frustration is a key parameter controlling electronic and magnetic properties of quantum spin liquid systems, yet remains challenging to tune. Here, we coherently drive molecular vibrations with midinfrared pulses in two organic quantum spin liquid candidates, the insulating $\kappa$-(BEDT-TTF)$_2$Cu$_2$(CN)$_3$ and the metallic $\kappa$-(BEDT-TTF)$_4$Hg$_{2.89}$Br$_8$, and probe their electronic response through ultrafast reflectivity measurements. We observe a nonlinear coupling between local molecular vibrations and nonlocal phonons, which is expected to directly modulate the geometric frustration of their triangular lattice. Our findings establish a promising route to dynamically control frustration in nonbipartite quantum materials.

cond-mat.str-el↗