Peter Krogstrup
YOU?
Author Swipe
View article: Band Offsets from Angle‐Resolved Valence Band Photoemission Spectroscopy
Band Offsets from Angle‐Resolved Valence Band Photoemission Spectroscopy Open
The conduction band offset ϕ 0 at semiconductor surfaces and interfaces is a crucial parameter for quantum devices exploiting proximity‐induced collective states such as superconductivity and magnetism. Recently, a method combining angle‐r…
View article: Identification of Soft Modes in Amorphous Al2O3${\rm Al}_{2}{\rm O}_{3}$ via First‐Principles
Identification of Soft Modes in Amorphous Al2O3${\rm Al}_{2}{\rm O}_{3}$ via First‐Principles Open
Amorphous is a fundamental component of modern superconducting qubits. While amorphous oxides offer distinct advantages, such as directional isotropy and a consistent bulk electronic gap, in realistic systems these compounds also support t…
View article: Data Catalog for: Flux-induced topological superconductivity in full-shell nanowires
Data Catalog for: Flux-induced topological superconductivity in full-shell nanowires Open
Data Catalog for: Flux-induced topological superconductivity in full-shell nanowires
View article: Spin-split superconductivity in spin-orbit coupled hybrid nanowires with ferromagnetic barriers
Spin-split superconductivity in spin-orbit coupled hybrid nanowires with ferromagnetic barriers Open
We report transport studies of hybrid Josephson junctions based on semiconducting InAs nanowires with fully overlapping epitaxial ferromagnetic insulator EuS and superconducting Al partial shells. Current-biased measurements reveal a hyste…
View article: Subgap transport in superconductor-semiconductor hybrid islands: Weak and strong coupling regimes
Subgap transport in superconductor-semiconductor hybrid islands: Weak and strong coupling regimes Open
Superconductor–semiconductor hybrid systems play a crucial role in realizing nanoscale quantum devices, including hybrid qubits, Majorana bound states, and Kitaev chains. For such hybrid devices, subgap states play a prominent role in thei…
View article: Many-body effects of two-level systems in superconducting qubits
Many-body effects of two-level systems in superconducting qubits Open
Superconducting qubits are often adversely affected by two-level systems (TLSs) within the Josephson junction, which contribute to decoherence and subsequently limit the performance of the qubit. By treating the TLS as a soft (i.e., low-fr…
View article: Identification of soft modes in amorphous Al$_{2}$O$_{3}$ via first-principles
Identification of soft modes in amorphous Al$_{2}$O$_{3}$ via first-principles Open
Amorphous Al$_{2}$O$_{3}$ is a fundamental component of modern superconducting qubits. While amphorphous oxides offer distinct advantages, such as directional isotropy and a consistent bulk electronic gap, in realistic systems these compou…
View article: Artificial Intelligence-Assisted Workflow for Transmission Electron Microscopy: From Data Analysis Automation to Materials Knowledge Unveiling
Artificial Intelligence-Assisted Workflow for Transmission Electron Microscopy: From Data Analysis Automation to Materials Knowledge Unveiling Open
(Scanning) transmission electron microscopy ((S)TEM) has significantly advanced materials science but faces challenges in correlating precise atomic structure information with the functional properties of devices due to its time-intensive …
View article: Subgap transport in superconductor--semiconductor hybrid islands: Weak and strong coupling regimes
Subgap transport in superconductor--semiconductor hybrid islands: Weak and strong coupling regimes Open
Superconductor--semiconductor hybrid systems play a crucial role in realizing nanoscale quantum devices, including hybrid qubits, Majorana bound states, and Kitaev chains. For such hybrid devices, subgap states play a prominent role in the…
View article: Ground-state phase diagram and parity-flipping microwave transitions in a gate-tunable Josephson junction
Ground-state phase diagram and parity-flipping microwave transitions in a gate-tunable Josephson junction Open
We probed a gate-tunable InAs nanowire Josephson weak link by coupling it to\na microwave resonator. Tracking the resonator frequency shift when the weak\nlink is close to pinch-off, we observe that the ground state of the latter\nalternat…
View article: Microwave spectroscopy of interacting Andreev spins
Microwave spectroscopy of interacting Andreev spins Open
Andreev bound states are fermionic states localized in weak links between superconductors which can be occupied with spinful quasiparticles. Microwave experiments using superconducting circuits with InAs/Al nanowire Josephson junctions hav…
View article: Gate-tunable superconductivity in hybrid InSb–Pb nanowires
Gate-tunable superconductivity in hybrid InSb–Pb nanowires Open
We present a report on hybrid InSb–Pb nanowires that combine high spin–orbit coupling with a high critical field and a large superconducting gap. Material characterization indicates the Pb layer of high crystal quality on the nanowire side…
View article: Supercurrent transport through 1$e$-periodic full-shell Coulomb islands
Supercurrent transport through 1$e$-periodic full-shell Coulomb islands Open
We experimentally investigate supercurrent through Coulomb islands, where island and leads are fabricated from semiconducting nanowires with fully surrounding superconducting shells. Applying flux along the wire yields a series of destruct…
View article: Collective formation of misfit dislocations at the critical thickness for equilibrium nanowire heterostructures
Collective formation of misfit dislocations at the critical thickness for equilibrium nanowire heterostructures Open
In this work we model the evolution of strain energy during different growth stages of heterostructure nanowires. We find that the minimum energy configuration changes abruptly from fully elastically strained to partially relaxed due to co…
View article: Lower-temperature fabrication of airbridges by grayscale lithography to increase yield of nanowire transmons in circuit QED quantum processors
Lower-temperature fabrication of airbridges by grayscale lithography to increase yield of nanowire transmons in circuit QED quantum processors Open
Quantum hardware based on circuit quantum electrodynamics makes extensive use of airbridges to suppress unwanted modes of wave propagation in coplanar-waveguide transmission lines. Airbridges also provide an interconnect enabling transmiss…
View article: InAs-Al hybrid devices passing the topological gap protocol
InAs-Al hybrid devices passing the topological gap protocol Open
Topological phases of matter can enable highly stable qubits with small footprints, fast gate times, and digital control. These hardware-protected qubits must be fabricated with a material combination in which a topological phase can relia…
View article: Origin of surface and subband states at the InAs(111)A surface
Origin of surface and subband states at the InAs(111)A surface Open
The atomic structure of surfaces and interfaces plays a vital role in the electronic quality and properties of quantum devices. The interplay between the surface and confined bulk subband states in terms of their susceptibility has been in…
View article: Epitaxially Driven Phase Selectivity of Sn in Hybrid Quantum Nanowires
Epitaxially Driven Phase Selectivity of Sn in Hybrid Quantum Nanowires Open
Hybrid semiconductor-superconductor nanowires constitute a pervasive platform for studying gate-tunable superconductivity and the emergence of topological behavior. Their low dimensionality and crystal structure flexibility facilitate uniq…
View article: Extreme enhancement of superconductivity in epitaxial aluminum near the monolayer limit
Extreme enhancement of superconductivity in epitaxial aluminum near the monolayer limit Open
BCS theory has been widely successful at describing elemental bulk superconductors. Yet, as the length scales of such superconductors approach the atomic limit, dimensionality as well as the environment of the superconductor can lead to dr…
View article: Epitaxially Driven Phase Selectivity of Sn in Hybrid Quantum Nanowires
Epitaxially Driven Phase Selectivity of Sn in Hybrid Quantum Nanowires Open
Hybrid semiconductor/superconductor nanowires constitute a pervasive platform for studying gate-tunable superconductivity and the emergence of topological behavior. Their low-dimensionality and crystal structure flexibility facilitate nove…
View article: InAs/MoRe Hybrid Semiconductor/Superconductor Nanowire Devices
InAs/MoRe Hybrid Semiconductor/Superconductor Nanowire Devices Open
Implementing superconductors capable of proximity-inducing a large energy gap in semiconductors in the presence of strong magnetic fields is a major goal toward applications of semiconductor/superconductor hybrid materials in future quantu…
View article: Threefold enhancement of superconductivity and the role of field-induced odd-frequency pairing in epitaxial aluminum films near the 2D limit
Threefold enhancement of superconductivity and the role of field-induced odd-frequency pairing in epitaxial aluminum films near the 2D limit Open
BCS theory has been widely successful at describing elemental bulk superconductors. Yet, as the length scales of such superconductors approach the atomic limit, dimensionality as well as the environment of the superconductor can lead to dr…
View article: Quantum capacitance of a superconducting subgap state in an electrostatically floating dot-island
Quantum capacitance of a superconducting subgap state in an electrostatically floating dot-island Open
We study a hybrid device defined in an InAs nanowire with an epitaxial Al shell that consists of a quantum dot in contact with a superconducting island. The device is electrically floating, prohibiting transport measurements, but providing…
View article: Few-mode to mesoscopic junctions in gatemon qubits
Few-mode to mesoscopic junctions in gatemon qubits Open
We investigate a semiconductor nanowire-based gatemon qubit with epitaxial Al on two facets of the nanowire, allowing gate control of wire density. Two segments have the Al removed, one forming a Josephson junction and the other operating …
View article: Radio-Frequency <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:mi>C</mml:mi></mml:math>-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:mi>V</mml:mi></mml:math> Measurements with Subattofarad Sensitivity
Radio-Frequency - Measurements with Subattofarad Sensitivity Open
We demonstrate the use of radio-frequency (rf) resonators to measure the capacitance of nanoscale semiconducting devices in field-effect transistor configurations. The rf resonator is attached to the gate or the lead of the device. Consequ…
View article: Mitigation of quasiparticle loss in superconducting qubits by phonon scattering
Mitigation of quasiparticle loss in superconducting qubits by phonon scattering Open
Quantum error correction will be an essential ingredient in realizing fault-tolerant quantum computing. However, most correction schemes rely on the assumption that errors are sufficiently uncorrelated in space and time. In superconducting…
View article: Photon-Assisted Tunneling of High-Order Multiple Andreev Reflections in Epitaxial Nanowire Josephson Junctions
Photon-Assisted Tunneling of High-Order Multiple Andreev Reflections in Epitaxial Nanowire Josephson Junctions Open
Semiconductor/superconductor hybrids exhibit a range of phenomena that can be exploited for the study of novel physics and the development of new technologies. Understanding the origin of the energy spectrum of such hybrids is therefore a …
View article: Scale-dependent optimized homoepitaxy of InAs(111)A
Scale-dependent optimized homoepitaxy of InAs(111)A Open
We combined in-situ scanning tunneling microscopy (STM) with the conventional growth characterization methods of atomic force microscopy (AFM) and reflection high energy electron diffraction (RHEED) to simultaneously assess atomic-scale im…