arXiv subjects

Chinmay K. Mohanty

Publications and source records attributed to Chinmay K. Mohanty.

3 recordsLinked to original sources

arXiv2026

Metallic-Phase-Fe$_3$GaTe$_2$ Enabled Interface Engineering for Self-Powered and High-Gain WS$_2$ Photodetectors

Two-dimensional transition-metal dichalcogenides offer strong light-matter interaction but suffer from inefficient carrier separation and contact-related losses in photodetectors. Here, we demonstrate a high-gain WS$_2$/Fe$_3$GaTe$_2$ van der Waals heterostructure photodetector, where metallic Fe$_3$GaTe$_2$ serves as an active interfacial contact. The work-function mismatch, together with interfacial charge redistribution and asymmetric contact geometry, contributes to a built-in field that supports self-powered photodetection at zero bias. Under 450 nm illumination, the device delivers a zero-bias responsivity of 23.5 A/W and an apparent external quantum efficiency of 6.4 x 10$^3$%. At -1 V biasing, the heterostructure exhibits photoresponse at 450, 520 and 633 nm, achieving a responsivity of 9.7 x 10$^3$ A/W and a noise derived specific detectivity of 2.3 x 10$^13$ Jones at 100 Hz under 450 nm illumination. The high photoresponse is attributed to interfacial carrier separation, efficient extraction, and a likely contribution from trap-assisted photogating in multilayer WS$_2$. These results establish Fe$_3$GaTe$_2$-enabled interface engineering as an effective route for self-powered, highly sensitive 2D photodetectors.

cond-mat.mtrl-sci↗

arXiv2026

Resonant Raman scattering in bilayer 3R-MoS$_{2}$

Raman scattering is a powerful spectroscopic technique widely employed to investigate light-matter interactions and lattice dynamics in two-dimensional materials. Here, we investigate the temperature-dependent resonant Raman response of bilayer 3R-MoS$_2$. The study combines multi-wavelength Raman spectroscopy, photoluminescence measurements, and density functional theory calculations to track the evolution of excitonic transitions and resonance conditions. We observe contributions from both zone-centre and finite-momentum phonons, a pronounced quenching of the Stokes intensity at low temperatures followed by saturation, the emergence of anti-Stokes scattering above 130~K, and a strong deviation of the effective phonon temperature from the lattice temperature induced by resonance effects. These results demonstrate that the Raman response is governed by the interplay between incoming and outgoing resonance processes, providing deeper insight into exciton-phonon coupling in van der Waals materials.

cond-mat.mtrl-sci↗

arXiv2026

Strong Spin-Lattice Interaction in Layered Antiferromagnetic CrCl$_\textrm{3}$

Understanding the coupling between lattice vibrations and magnetic order is crucial for controlling properties of two-dimensional magnetic materials. Here, we investigate the vibrational properties of bulk and thick-flake CrCl$_\textrm{3}$ using polarization-resolved Raman spectroscopy, complemented by photoluminescence, photoluminescence excitation, and optical absorption measurements. Symmetry analysis, supported by first-principles phonon calculations, enables the unambiguous assignment of all eight Raman-active modes, four $\textrm{A}_\textrm{g}$ and four $\textrm{E}_\textrm{g}$, previously predicted only theoretically. Excitation-energy-dependent measurements reveal that the strong enhancement of selected phonon modes originates primarily from interference effects rather than resonant Raman scattering. Temperature-dependent Raman spectroscopy further reveals pronounced signatures of spin-phonon coupling across the transition from a fully antiferromagnetic phase, through an intermediate regime with local, domain-like ferromagnetic order, to the paramagnetic phase, accompanied by a clear rhombohedral-to-monoclinic structural transition. Together, these results demonstrate how lattice, electronic, and magnetic degrees of freedom collectively govern the Raman response of CrCl$_\textrm{3}$.

cond-mat.mtrl-sci↗