arXiv subjects

Renu Rani

Publications and source records attributed to Renu Rani.

2 recordsLinked to original sources

arXiv2025

Polarization of photoluminescence by optically driven orbital reconstruction in magnetically ordered CrCl3

Control of magnetic order through optical manipulation of orbital states can be realized in a wide range of materials, including insulators. In the latter case, electrons are excited into different electronic states, whose character may be a complex result of spin-orbit-lattice coupling. Here, we use a combination of polarization-resolved photoluminescence spectroscopy and density functional theory calculations to study excited Cr3+ ions in bulk, insulating antiferromagnetic CrCl3. Our results demonstrate a temperature-dependent preferential polarization direction below ~17 K, which reorients in the presence of an applied in-plane magnetic field. Density functional theory calculations reveal a local distortion of the ligand field and the generation of out-of-plane spin and orbital moments, following Cr3+ ion excitation. These changes link the photoluminescence polarization to the magnetic state of CrCl3. Our findings provide insight into the excited-state electronic structure of Cr3+ ions and suggest that CrCl3 is a promising candidate for opto-orbitronic applications.

cond-mat.mtrl-sci↗

arXiv2024

Single MoS2-flake as a high TCR non-cryogenic bolometer

Temperature coefficient of resistance (TCR) of a bolometer can be tuned by modifying the thermal conductance of an absorbing materials since they sense radiations via the temperature change in the absorber. However, the thermal conductance of the absorber can be reduced by engineering the appropriate thermal isolation, which can be an ultimate solution towards making a highly sensitive thermal detector. Here, we have developed an atomically thin 2D bolometer detector made up of a mechanically transferred suspended multilayer-MoS2 flake, eliminating the use of challenging thin-film fabrication process. The strength of our detector lies on the two factors: its large surface-to-volume window to absorb the radiations; the suspended configuration which prevents the heat dissipation through the substrate and therefore reduces the thermal conductance. The bolometric response of the detector is tested in both modes, via the photoresponse and the thermal response. The prototype is found to exhibit a very high TCR ~ -9.5%/K with the least achievable thermal noise-equivalent power (NEP) ~ 0.61 pWHz-1/2, in ambient conditions at 328 K.

physics.app-ph↗