Institute of Physics PAS

Artistic visualization of the non-Hermitian Fermi-Dirac distribution (shown in the background 3D plot) and its impact on persistent current transport in a superconducting-normal-superconducting junction (blue-green-blue). The junction is coupled to an external environment (violet), showcasing the dissipative nature of the quantum transport process.

2024-10-01
Osiągnięcia

Fermi-Dirac Distribution Reformulated in Non-Hermitian Systems

Researchers have extended the traditional Fermi-Dirac distribution to non-Hermitian systems. This new formalism provides a general framework to compute quantum many-body observables in equilibrium systems coupled to dissipative environments.

(left) The diffusion of the intrinsically disordered protein (green) is slower than that of a protein with a globular structure (black), even though the green protein has a much lower molecular mass and a shorter chain, as shown by the autocorrelation curves measured by fluorescence correlation spectroscopy. (right) The coarse-grained globule-linker model allows rapid calculation of the hydrodynamic radii of intrinsically disordered proteins in agreement with experimentally measured results.

2024-09-13
Osiągnięcia

Hydrodynamic properties of intrinsically disordered proteins

Intrinsically disordered proteins (IDPs), essential for regulating critical cellular functions, have long posed research challenges due to their lack of fixed three-dimensional structure. They are now more accessible for study thanks to a new model that enables rapid and precise analysis of their hydrodynamic properties, marking a significant breakthrough in biophysical research.

A: Layout of the studied nanostructure consisting of an Single Vortex Box (SVB), a Dayem nanobridge, and narrow connecting leads. The Lorentz force FL is exerted on the vortex by the applied current IL in the presence of perpendicular magnetic field B. B: The as-received experimental vortex stability diagram. Switching current dependence of the nanobridge on the applied perpendicular magnetic field B and the amplitude of the Lorentz pulse IL. The slope of Iexp, indicated with dashed line, mark the minimum value of the Lorentz pulse necessary to expel the vortex for a given magnetic field B. C: Experimental thermal dynamics of the SVB after expulsion of a single vortex measured under conditions denoted by the circle on the vortex stability diagram. The broken line represents the exponential fit in the linear regime. D: The pulse protocol used in the experiment.

2024-09-02
Osiągnięcia

Quantum thermodynamics with a single superconducting vortex

We control and monitor the state of the single superconducting vortex. Using our fastest thermometer in the nanoworld, we measured the thermal transient due to the vortex expulsion from the superconductor. An energy dissipated due to this expulsion is equivalent to the absorption of a single photon of the visible light.

(a) Cross section of the pentangonal nanowire obtained using scanning transmission electron microscopy; the inset shows the disclination and core chain (CC). (b) Electronic structure with red bands from the core linking the valence and conduction bands; (c) reversing anions and cations.

2024-08-12
Osiągnięcia

Pentagonal nanowires from topological crystalline insulators: a platform for intrinsic core-shell nanowires and higher-order band topology

We report on the first experimental realization of pentagonal nanowires within ionic compounds using Pb1-xSnxTe. The structures are potential candidates for realizing higher-order topology. The disclination and twin boundaries cause the states originating from the core region to generate a conducting band connecting the valence and conduction bands forcing a metallic phase.

Left panel: The crystal structure of the α-Sn layer grown by MBE on CdTe/GaAs substrate undergoes biaxial compressive deformation in the plane (black arrows) and, therefore, uniaxial tensile deformation along the layer normal to the plane. The magnetic field B can be applied in the plane of the layer. Center panel: States of the surface α-Sn layers in the deformation-induced Dirac semimetal phase (B=0), observed using angular-resolved photoemission spectroscopy (ARPES). Right panel: The negative longitudinal magnetoresistance (current I ǁ B, see the right inset) indicating a chiral anomaly in the Weyl semimetal phase induced by the in-plane magnetic field (B). At low temperatures (T) and in weak fields (B), Shubnikov-de Hass oscillations are also visible. The insets to the middle and right panels show the calculated ±-Sn band structure for the Dirac semimetal phase and the Weyl phase, respectively.

2024-06-19
Osiągnięcia

Unique electronic properties of gray tin

The seemingly ordinary and well-known material, tin, exhibits unique electronic properties under extreme but well controlled conditions. The discovery that it turns into Dirac and Weyl semimetals was made by an international team of researchers led by scientists from the International Research Center MagTop, at the Institute of Physics.

We have demonstrated the hybridization between the gapped edge state and the gapless surface state. In the first (left) column, the free-standing monolayer exhibits a gapped edge state. The second (middle) column demonstrates that the clean surface of gray arsenic (As) features a gapless Rashba surface state near the Fermi level. In the third (right) column, with the introduction of monolayer step edges, the edge state undergoes hybridization with the gapless surface states, resulting in the emergence of gapless edge states at the step edges.

2024-05-16
Osiągnięcia

A hybrid topological quantum state in elemental solid arsenic

An international team of scientists including dr Rajibul Islam from the Institute of Physics P.A.S. has demonstrated that the observed step-edge states in α-As, unlike surface or hinge states, are not expected for either first or higher-order topological insulators separately but only for hybrid materials in which both kinds of band topology are present.

2024-03-04
Research highlights

Signatures of a surface spin-orbital chiral metal

In an article published in the journal Nature, signatures of spin-orbital currents breaking both time-reversal and all crystalline symmetries were confirmed in an exotic surface chiral phase of Sr2RuO4. It was possible to find signatures of the sought for spin-orbital currents thanks to the use of the circularly-polarized angular- and spin-resolved photoemission technique CP-spin ARPES through contributions...