arXiv subjects

Prasad Muragesh

Publications and source records attributed to Prasad Muragesh.

4 recordsLinked to original sources

arXiv2026

Coplanar Lateral Gating MoS2 on SrTiO3: A Unified Platform for Classical and Quantum Devices

Atomically thin transition-metal dichalcogenides, such as MoS2, offer a promising route to surpass the scaling limits of silicon owing to their excellent electrostatic control and resilience to short-channel effects. Realizing this potential depends critically on gate-stack engineering, where strong gate coupling must be achieved without compromising the pristine two-dimensional interface. Here, we demonstrate a coplanar lateral-gating architecture for MoS2 field-effect transistors fabricated directly on single-crystal SrTiO3. The exceptionally high permittivity of SrTiO3 enhances gate-channel coupling. The coplanar geometry eliminates the need for a separate gate insulator, reducing interface disorder. Owing to the quantum paraelectric nature, the SrTiO3 dielectric constant increases upon cooling, enhancing the gate coupling, leading to a decrease in threshold voltage and subthreshold swing an effect that contrasts with conventional FET architectures. The dielectric-free MoS2 surface, combined with enhanced electrostatic control, makes this architecture a promising platform for low-power two-dimensional electronics and cryogenic quantum devices.

cond-mat.mes-hall↗

arXiv2026

Cascaded Four-Wave Mixing on Quantum Paraelectrics for On-chip Cryogenic Microcombs

Here, we demonstrate an on-chip cryogenic microwave frequency-comb on a planar superconducting resonator fabricated on Strontium titanate(STO), a quantum paraelectric material. The material's Kerr-type nonlinearity arising from the quantum paraelectric phase, an underexplored state, enables pronounced resonance shifts, Duffing-like bifurcations and comb generation via cascaded foure-wave mixing. Our results establish STO resonators as a low power, cryogenically compatible platforms for nonlinear microwave photonics, with applications in scalable quantum control and on-chip frequency synthesis.

cond-mat.mes-hall↗

arXiv2026

Cryogenic microwave frequency combs based on quantum paraelectric superconducting resonators

A frequency comb, known for its precision as an "optical ruler", features an evenly spaced spectral pattern. While these combs are vital in photonic quantum technologies, their microwave counterparts are now highly sought after for cryogenic quantum technologies, including semiconducting and superconducting qubits and quantum electrical metrology, which mainly operate in the microwave regime. However, microwave combs are still largely underexplored, and typically rely on complex, high-power optical systems incompatible with the low-power, cryogenic on-chip quantum technologies. In this manuscript, we present an all-electrical, on-chip, cryogenic microwave frequency comb on Strontium Titanate (SrTiO$_3$), exploiting its Pockels-like effect in its quantum paraelectric phase. Our device, utilizing a superconducting microwave cavity, generating the frequency comb via cavity phase modulation enabled by the field-induced effective $χ(2)$ of SrTiO$_3$. The ability to continuously vary the dielectric constant of SrTiO$_3$ by the application of electric field, in its quantum paraelectric phase, makes it possible to control the comb's operating frequency range. The exceptionally high dielectric constant of SrTiO$_3$, > 20,000 in its quantum paraelectric state, enables an ultra-miniature design and on-chip integration with cryogenic quantum technologies.

cond-mat.mes-hall↗

arXiv2025

Active Noise Reduction in Si/SiGe Gated Quantum Dots

Solid-state quantum technologies such as quantum dot qubits and quantum electrical metrology circuits rely on quantum phenomena at ultra-low energies, making them highly sensitive to various forms of environmental noise. Conventional passive filtering schemes can reduce high-frequency noise but are often ineffective against low-frequency interference, like powerline or instrument-induced. Extending such filters to lower frequencies causes practical issues such as longer stabilization times, slower system response, and increased Johnson noise, which impede low-frequency transport measurements. To address these limitations, we propose and experimentally demonstrate a generalized active noise cancellation scheme for quantum devices operating at sub-Kelvin temperatures. Our approach compensates periodic environmental interference by dynamically injecting a phase-coherent anti-noise signal directly into the device. We employ an automated feedback protocol featuring beat-frequency reduction and adaptive phase-amplitude tuning, enabling real-time compensation without any manual intervention. Unlike post-processing or passive filtering, this method suppresses noise at the device level without introducing additional time constants. We implement the scheme on a gate-defined Si/SiGe quantum dot subject to strong 50 Hz powerline interference and validate its effectiveness through acquiring Coulomb Blockade Oscillations and Coulomb diamond plots. The technique achieves substantial suppression of both the targeted interference and the overall noise floor, thereby stabilizing transport characteristics and enhancing device fidelity. While demonstrated on a quantum dot, the proposed framework is broadly applicable to a wide class of solid-state quantum devices where deterministic noise presents a critical bottleneck.

cond-mat.mes-hall↗