arXiv subjects

Anze Mraz

Publications and source records attributed to Anze Mraz.

5 recordsLinked to original sources

arXiv2026

A programmable superconductor created by light

The quest for superconductivity created by light extends for more than half a century, yet direct evidence of a true zero-resistance state - whose macroscopic quantum phase coherence is both created and controlled by light - has remained elusive. Here we report for the first time on a complex but robust light-programmable superconducting (LiPS) state at an aluminium-silicon heterojunction that is created and fully controlled with femtosecond laser pulses. The superconducting critical temperatures - ranging from 1.8 to 8.5 K, can be increased or erased at will by the application of tailored pulse sequences. At low temperatures the LiPS state shows features characteristic of a Berezinski-Kosterlitz-Thouless topological transition, but another distinct state appears at temperatures above 2 K, which shows clear signatures of quantum phase disorder. In the presence of a magnetic field we observe behaviour characteristic of vortex pinning and creep consistent with the 2-dimensional (2D) nature of the phase coherent system. The origin of the LiPS effect is attributed to light pulse control of the Moire-like superlattice of misfit dislocations (MDs) arising from discommensurations between the Al and Si lattices which is visible by high-resolution electron microscopy. We show how light pulses can be used to control the superlattice periodicity and highlight the appearance of topologically protected soliton-like kinks along the dislocation lines, important for imparting controllable metastability to the system. The demonstration of LiPS paves the way for designing metastable superconducting devices with controllable phase-coherence, enabling applications such as light-engineered quantum circuits, local gap tuning in quantum processors, and optically switchable superconducting devices.

cond-mat.supr-con↗

arXiv2024

Imaging of electrically controlled van der Waals layer stacking in 1T-TaS2

Van der Waals (vdW) materials exhibit a variety of states that can be switched with low power at low temperatures, offering a viable cryogenic "flash memory" required for the classical control electronics for solid-state quantum information processing. In 1T-TaS2, a non-volatile metallic 'hidden' state can be induced from an insulating equilibrium charge-density wave ground state using either optical or electrical pulses. Given that conventional memristors form localized, filamentary channels which support the current, a key question for design concerns the geometry of the conduction region in highly energy-efficient 1T-TaS2 devices. Here, we report in operando micro-beam X-ray diffraction, fluorescence, and concurrent transport measurements, allowing us to spatially image the non-thermal hidden state induced by electrical switching of 1T-TaS2. Our results reveal a long-range ordered, non-filamentary switched state that extends well below the electrodes, implying that the self-organized, collective growth of the hidden phase is driven by a combination of charge flow and lattice strain. Our unique combination of techniques showcases the potential of non-destructive, three-dimensional X-ray imaging to study bulk switching properties in microscopic detail, namely electrical control of the vdW layer stacking.

cond-mat.str-el↗

arXiv2023

A high-efficiency programmable modulator for extreme ultraviolet light with nm feature size based on an electronic phase transition

The absence of efficient light modulators for extreme ultraviolet (EUV) and X-ray photons significantly limits their real-life application, particularly when even slight complexity of the beam patterns is required. Here we report on a novel approach to reversible imprinting of a holographic mask in an electronic Wigner crystal material with a sub-90 nm feature size. The structure is imprinted on a sub-picosecond time-scale using EUV laser pulses and acts as a high-efficiency diffraction grating that deflects EUV or soft X-ray light. The imprinted nanostructure is stable after the removal of the exciting beams at low temperatures but can be easily erased by a single heating beam. Modeling shows that the efficiency of the device can exceed 1%, approaching state-of-the-art etched gratings, but with the benefit of being programmable and tunable over a large range of wavelengths. The observed effect is based on the rapid change of lattice constant upon transition between metastable electronically-ordered phases in a layered transition metal dichalcogenide. The proposed approach is potentially useful for creating tunable light modulators in the EUV and soft X-ray spectral ranges.

physics.optics↗

arXiv2022

Nanocryotron-driven Charge Configuration Memristor

Cryo-computing - both classical and quantum, is severely limited by the absence of a suitable cryo-memory. The challenge both in terms of energy efficiency and speed have been known for decades, but so far conventional technologies have not been able to deliver adequate performance. Here we present a novel non-volatile memory device which incorporates a superconducting nanowire and an all-electronic charge configuration memristor (CCM) based on switching between charge-ordered states in a layered dichalcogenide material. We investigate the time-dynamics and current-voltage characteristics of such a device fabricated using a NbTiN nanowire and a 1T-TaS2 CCM. The observed dynamical response of the device is faithfully reproduced by modelling of the superconducting order parameter showing versatility of application. The inherent ultrahigh energy efficiency and speed of the device, which is compatible with single flux quantum logic, leads to a promising new memory concept for use in cryo-computing and quantum computing peripheral devices.

physics.comp-ph↗

arXiv2021

Energy efficient manipulation of topologically protected states in non-volatile ultrafast charge configuration memory devices

Non-volatile magnetic storage, from 1940s magnetic core to present day racetrack memory and magnetic anisotropy switching devices rely on the metastability of magnetic domains to store information. However, the inherent inefficiency of converting the information-carrying charge current into magnetization switching sets fundamental limitations in energy consumption. Other non-magnetic non-volatile memories such as memristors, ferroelectric memory and phase change memory devices also rely on energetically relatively costly crystal structural rearrangements to store information. In contrast, conventional electronic charge states in quantum dots for example, can be switched in femtoseconds with high efficiency, but any stored information dissipates rapidly. Here we present a radically different approach in the form of a charge-configuration memory (CCM) device that relies on charge-injection-driven electronic crystal melting and topological protection of the resulting electronic domain configurations of a two-dimensional electronic crystal to store information. With multiprobe scanning tunneling microscopy (STM) we show microscopically, within an operational device, how dislocations in the domain ordering lead to metastability by a mechanism that is topologically equivalent to magnetic bubble memory. The devices have a very small switching energy (<2.2 fJ/bit), ultrafast switching speed of <11 ps and operational range over more than 3 orders of magnitude in temperature (<250 mK ~ 190 K). Together with their simple functionality, a large resistance switching ratio, straightforward fabrication and impressive endurance, CCM devices introduce a new memory paradigm in emerging cryo-computing and other high-performance computing applications that require ultrahigh speed and low energy consumption.

cond-mat.str-el↗