arXiv subjects

Kartick Biswas

Publications and source records attributed to Kartick Biswas.

5 recordsLinked to original sources

arXiv2026

Berry Curvature Driven Transport in Silicon-Compatible Altermagnetic $α$-MnTe Thin Films

Integrating spin-dependent functionality with mainstream semiconductor technology is a central goal of modern spintronics, yet most candidate materials remain incompatible with silicon-based platforms. Here, we report the direct epitaxial integration of $α$-MnTe thin films on Si(111) via molecular beam epitaxy and demonstrate a robust anomalous Hall effect (AHE) in this silicon-compatible altermagnetic system. Despite the absence of net bulk magnetization, the films exhibit a pronounced hysteretic Hall response, providing transport evidence consistent with finite Berry curvature generated by symmetry breaking in the thin-film geometry. High-resolution structural and spectroscopic characterization confirms phase-pure, epitaxial growth with hexagonal NiAs-type symmetry, while magnetotransport measurements reveal correlated hysteresis in both transverse and longitudinal channels with systematic temperature evolution. First-principles calculations reveal substantial uncompensated Berry curvature arising from the spin-split band structure, consistent with altermagnetic symmetry and the origin of the observed Hall response. These results establish MnTe/Si(111) as a silicon-compatible altermagnetic platform and chart a concrete pathway for embedding Berry-phase-driven functionalities into scalable semiconductor device architectures.

cond-mat.mtrl-sci↗

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↗

arXiv2026

Room-Temperature Electric-Field Control of Anomalous Hall Effect in Py/BTO/LSMO Heterostructures

We demonstrate room temperature electric field control of the anomalous Hall effect in epitaxial Ni80Fe20 (Py) BaTiO3 (BTO) La0.7Sr0.3MnO3 (LSMO) thin film heterostructures grown on MgO and LaAlO3 substrates. Substrate induced strain states generate distinct magnetic anisotropies, enabling voltage driven tuning between anomalous and topological Hall contributions. Robust ferroelectric polarization in BTO, confirmed by piezoresponse force microscopy, couples strongly to interfacial orbital reconstruction and carrier redistribution. As a result, Hall resistivity exhibits giant low voltage tunability, with up to nearly 93 percent modulation at operating voltages of only 0.5 tand 2 V. Density functional theory calculations further reveal polarization controlled Rashba spin splitting, establishing a direct link between ferroelectric order and emergent quantum transport. These findings establish Py/BTO/LSMO heterostructures as promising candidates for low-power multifunctional spintronic devices, where substrate engineering enables control over emergent quantum transport phenomena.

cond-mat.mtrl-sci↗

arXiv2025

Interfacial and bulk switching MoS2 memristors for an all-2D reservoir computing framework

In this study, we design a reservoir computing (RC) network by exploiting short- and long-term memory dynamics in Au/Ti/MoS$_2$/Au memristive devices. The temporal dynamics is engineered by controlling the thickness of the Chemical Vapor Deposited (CVD) MoS$_2$ films. Devices with a monolayer (1L)-MoS$_2$ film exhibit volatile (short-term memory) switching dynamics. We also report non-volatile resistance switching with excellent uniformity and analog behavior in conductance tuning for the multilayer (ML) MoS$_2$ memristive devices. We correlate this performance with trap-assisted space-charge limited conduction (SCLC) mechanism, leading to a bulk-limited resistance switching behavior. Four-bit reservoir states are generated using volatile memristors. The readout layer is implemented with an array of nonvolatile synapses. This small RC network achieves 89.56\% precision in a spoken-digit recognition task and is also used to analyze a nonlinear time series equation.

cs.ET↗

arXiv2024

Epitaxial growth and stabilization of perovskite phase EuNiO3 thin films through RF sputtering

Phase change materials (PCMs) that exhibit volatile resistive switching are promising for emulating neuronal oscillators. Charge transfer insulators, such as ReNiO3 (where Re represents rare earth metals like Pr, Nd, Sm, Eu...), form a family of PCMs with tunable metal-insulator transition (MIT) temperatures across a broad range. Notably, MIT can be adjusted via chemical doping or strain engineering. EuNiO3, in particular, is an attractive choice for oscillator devices given its bulk transition temperature (TMI) of approximately 190°C, which is well above room temperature, reducing crosstalk issues while remaining low enough to support energy-efficient applications. We demonstrate a method to stabilize high-quality epitaxial EuNiO3 thin films through scalable reactive RF sputtering and post-annealing, optimizing oxygen partial pressures and annealing temperatures across two substrates. Growth at low or zero oxygen partial pressures resulted in amorphous samples, while higher pressures improved crystallinity but led to the stabilization of Ruddlesden-Popper (RP) phases [An+1BnO3n+1] and associated faults. Post-annealing enhanced crystallinity in all samples, transforming RP phases and faults toward the perovskite phase. We conducted operando XRD and transport measurements on our films, finding the transition temperatures of perovskite phase samples grown on LAO and LSAT to be approximately 300°C and 250°C, respectively. We attribute the increase in TMI for LAO samples to in-plane compressive strain (-0.76%), which reduces the Ni-O-Ni bond angles in-plane. Similarly, LSAT samples experience in-plane tensile strain (2.1%), which decreases out-of-plane Ni-O-Ni bond angles, increasing TMI compared to bulk. However, this is counteracted by oxygen vacancies due to lowered formation energies. Films that stabilized in RP phases did not exhibit any transition.

cond-mat.mtrl-sci↗