arXiv subjects

Arup Basak

Publications and source records attributed to Arup Basak.

3 recordsLinked to original sources

arXiv2026

Interplay of spin-lattice and electronic coupling far above Neel ordering in 2D antiferromagnetic CrPS4 and its interface manifestation

A short-range spin correlation driven, strongly intercoupled spin-phonon-electronic state far above TN (~38K) is identified in the low dimensional van der Waals antiferromagnet CrPS4. Temperature-dependent Raman spectroscopy reveals spin-phonon coupling persisting up to T*~120K, concomitant with local lattice distortion. The setting of vibronic progression in photoluminescence spectra suggests the strengthening of electron-phonon coupling around T*. Furthermore, both the electrical transport and optoelectronic response also change significantly at T*. The results indicate that spin-phonon coupling above TN in CrPS4 originates from local lattice distortion induced by short range magnetic correlations which in turn enhances the electron-phonon interaction. Furthermore, using a CrPS4/In2Se3 heterostructure, we demonstrate that the anomaly associated with the coupled degrees of freedom in CrPS4 also influences the adjacent In2Se3 layer. The lattice dynamics of In2Se3 is significantly modified across the magnetic anomaly of CrPS4, and the coupled dynamics is observed at T*. These interfacial manifestation opens up new possibilities for achieving correlated multifunctionalities in artificially designed heterostructure.

cond-mat.mtrl-sci↗

arXiv2025

Field-induced reversible phase transition and negative differential resistance in In2Se3 ferroelectric semiconducting FETs

Indium selenide (In2Se3), a ferroelectric semiconductor, offers a unique platform for multifunctional nanoelectronics owing to the interplay between polarization dynamics, interlayer sliding, and structural polymorphism. Ferroelectric semiconductor field-effect transistors (FeS-FETs) provide an ideal architecture to harness this coupling. Here, we demonstrate gate-tunable negative differential resistance (NDR) with high peak-to-valley ratios and hysteretic output conductance in In2Se3 FeS-FETs. Combining high-resolution electron microscopy with electrical transport measurements, we attribute the NDR to a field-induced, volatile phase transition from a low-resistance alpha-2H phase to a high-resistance state. Atomic scale ex-situ imaging reveals that in-plane electric fields (Vd) drive interlayer sliding, rotational misalignments that generate Moire patterns, and intralayer shear-together producing stress induced phase transitions. Out-of-plane field however results in robust non-volatile polarization switching. These mechanistic insights highlight both the promise of two dimensional ferroelectric devices for multifunctional nanoelectronics and alternative computing paradigms, and the intrinsic limitations of In2Se3 field-effect transistors for conventional ferroelectric memory applications.

cond-mat.mtrl-sci↗

arXiv2025

Anion Doping Driven Non-Ferroelectric-to-Ferroelectric Phase Transition in Epitaxial Y:HfO2

Oxygen vacancies are often essential for stabilizing the orthorhombic ferroelectric phase in HfO2, with cationic doping widely employed to introduce such defects. In contrast, systematic studies on anionic doping to induce ferroelectricity remains largely in nascent stages. Here, using epitaxial Y:HfO2 films grown on ITO-buffered YSZ substrates that initially crystallize predominantly in the monoclinic non-polar phase, we demonstrate that post-deposition rapid thermal annealing in N2 atmosphere at 900 {\deg}C enables nitrogen incorporation without disrupting epitaxy. As the annealing duration increases from 10 s to 2 min, the monoclinic phase diminishes, accompanied by the emergence of robust ferroelectric hysteresis and a corresponding increase in the orthorhombic phase fraction. Combining independent spectroscopic and compositional analyses, we experimentally establish that nitrogen preferentially incorporates into pre-existing neutral oxygen-vacancy sites, converting them into charged oxygen vacancies that drive the transformation from the non-polar monoclinic phase to the ferroelectric orthorhombic phase. Our epitaxial model platform therefore reveals an anion-mediated defect-engineering pathway for controlling ferroelectricity in Y:HfO2, establishing nitrogen incorporation not merely as a chemical dopant, but as a route to fundamentally reconfigure the defect thermodynamics governing phase stability in fluorite ferroelectrics.

cond-mat.mtrl-sci↗