arXiv subjects

Naresh Shyaga

Publications and source records attributed to Naresh Shyaga.

4 recordsLinked to original sources

arXiv2026

Anomalous Hall Effect in Silicon-Compatible Altermagnetic alpha-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 alpha-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 magnetization, the films exhibit a pronounced hysteretic Hall response, providing clear evidence of 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

Vortex Transport in Ni/Bi Bilayer Superconductor with Strong Spin-Orbit and Exchange Interaction

Nickel/bismuth (Ni/Bi) bilayers are a promising platform for exploring unconventional superconductivity. Ferromagnetic Ni is coupled to Bi, a strong spin orbit metal that only becomes superconducting below approx 10 mK, forming a bilayer exhibits superconductivity at a much higher temperatures, a Tc of 3 to 4 K. Such a bilayer thus makes an ideal system to probe Cooper pairing in strong spin orbit coupled magnetic environments. Magneto transport studies near Tc reveal the behavior of vortex dynamics and exchange proximity effects. It is seen that isolated vortices of the bilayers respond sensitively to out of plane fields, producing antisymmetric transverse resistance peaks attributable to competing Magnus and viscous forces. Control experiments using a ferromagnetic insulator confirm that superconductivity extends throughout the bilayer, not just confined at the interface. Overall, the results provide a unified picture of transport dominated by vortex dynamics and show that a conventional s wave order parameter accounts for the observations, with any likely unconventional contributions being only subtle.

cond-mat.supr-con↗

arXiv2026

Crystallographic Orientation-Dependent Magnetotransport in the Layered Antiferromagnet -- CrSBr

Among two-dimensional magnetic materials, CrSBr has attracted considerable attention owing to its coexistence of ferromagnetic and antiferromagnetic ordering, which depends sensitively on crystallographic orientation. An additional distinguishing feature of CrSBr is its highly anisotropic Fermi surface in momentum space. In this work, we present a comprehensive investigation of magnetoresistance by systematically orienting the bias current and the applied magnetic field along all three crystallographic axes. We demonstrate that the magnetoresistance serves as a direct probe of electronic anisotropy, exhibiting pronounced variations when the current is applied along different crystallographic directions under a magnetic field perpendicular to the sample plane. For in-plane magnetic fields, we observe conventional anisotropic magnetoresistance accompanied by hysteresis, indicative of ferromagnetic behavior. Overall, our study provides a complete picture of electronic transport in CrSBr as a function of bias current and magnetic field orientation with respect to crystallographic directions, thereby opening pathways for future experiments requiring high sensitivity of electrical resistance to magnetic field gradients.

cond-mat.mtrl-sci↗

arXiv2025

Time Reversal Symmetry Broken Electronic Phases in Thin Films of Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$

High-temperature superconductors (high-Tc SCs) host a rich landscape of electronic phases encompassing the pseudogap, strange metal, superconducting, antiferromagnetic insulating, and Fermi-liquid regimes. The superconducting phase is notable for non-dissipative electronic functionality at relatively high temperatures. These phases are commonly probed in thermodynamic phase space by varying temperature or current through the sample. They can also be probed by breaking time-reversal symmetry (TRS) with an external magnetic field, which yields transition signatures distinct from those arising solely from temperature or current tuning. Here we show that electron transport in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ is primarily governed by two-dimensional superconductivity consistent with a Berezinskii-Kosterlitz-Thouless (BKT) topological phase transition, as supported by current-voltage characteristics measured under temperature variation; these measurements preserve TRS. In contrast, when an external magnetic field is applied, the superconducting state is consistently preceded by weak antilocalization (WAL), where bound vortex-antivortex pairs dissociate into a normal metallic state through an intermediate localized phase. We further establish that highly disordered films exhibit transport dominated by three-dimensional weak localization, with superconductivity entirely suppressed.

cond-mat.supr-con↗