arXiv subjects

Justus Teller

Publications and source records attributed to Justus Teller.

4 recordsLinked to original sources

arXiv2025

Fabrication Optimization of Suspended Stencil Mask Lithography for Multi-Terminal Josephson Junctions

Stencil mask lithography is an advanced technique for fully in-situ fabricating Josephson junctions, which is increasingly being used for multi-terminal Josephson junctions. This study provides information on the optimal mask design and mask reliability. For this, 270 mask designs were systematically fabricated and investigated under scanning electron microscope. Reliable statements are made about mask yield, minimal dimensions, and systematic dependencies on the number of superconducting terminals. We find that stencil mask lithography can be used reliably for fabricating multi-terminal Josephson junctions, enabling lateral mask dimensions down to 40$\,$nm on average.

physics.app-ph↗

arXiv2025

Frustrated Frustration of Arrays with Four-Terminal Nb-Pt-Nb Josephson Junctions

We study the frustration pattern of a square lattice with in-situ fabricated Nb-Pt-Nb four-terminal Josephson junctions. The four-terminal geometry gives rise to a checker board pattern of alternating fluxes f, f' piercing the plaquettes, which stabilizes the Berezinskii-Kosterlitz-Thouless transition even at irrational flux quanta per plaquette, due to an unequal repartition of integer flux sum f+f' into alternating plaquettes. This type of frustrated frustration manifests as a beating pattern of the dc resistance, with state configurations at the resistance dips gradually changing between the conventional zero-flux and half-flux states. Hence, the four-terminal Josephson junction array offers a promising platform to study previously unexplored flux and vortex configurations, and provides an estimate on the spatial expansion of the four-terminal Josephson junction central weak link area.

cond-mat.supr-con↗

arXiv2023

Current-induced magnetization switching in a magnetic topological insulator heterostructure

We present the current-induced switching of the internal magnetization direction in a magnetic topological insulator/topological insulator heterostructure in the quantum anomalous Hall regime. The switching process is based on the bias current dependence of the coercive field, which is attributed to the effect of the spin-orbit torque provided by the unpolarized bias current. Increasing the bias current leads to a decrease in the magnetic order in the sample. When the applied current is subsequently reduced, the magnetic moments align with an externally applied magnetic field, resulting in repolarization in the opposite direction. This includes a reversal of the spin polarisation and hence a reversal of the chiral edge mode. Possible applications in spintronic devices are discussed.

cond-mat.mes-hall↗

arXiv2023

Fourier transformation based analysis routine for intermixed longitudinal and transversal hysteretic data for the example of a magnetic topological insulator

We present a symmetrization routine that optimizes and eases the analysis of data featuring the anomalous Hall effect. This technique can be transferred to any hysteresis with (point-)symmetric behaviour. The implementation of the method is demonstrated exemplarily using intermixed longitudinal and transversal data obtained from a chromium-doped ternary topological insulator revealing a clear hysteresis. Furthermore, by introducing a mathematical description of the anomalous Hall hysteresis based on the error function precise values of the height and coercive field are determined.

cond-mat.mes-hall↗