Phase-controlled minimal Kitaev chain in multiterminal Josephson junctions

TL;DR

This paper proposes a phase-controlled Josephson junction device that creates and detects Majorana modes without magnetic fields, using phase tuning and conductance measurements in a semiconductor setup.

Contribution

It introduces a novel multiterminal Josephson junction design for realizing Majorana modes without magnetic fields, enhancing material compatibility and detection methods.

Findings

Numerical simulations confirm the emergence of PMM modes under specific phase conditions.

The device design allows detection of Majorana modes via conductance measurements.

Elimination of magnetic fields broadens material applicability and improves energy resolution.

Abstract

We propose a nanodevice based on multi-terminal Josephson junctions for the creation and detection of poor man's Majorana (PMM) modes. The device consists of a double three-terminal Josephson junction (3TJJ) embedded in a planar semiconductor that engineers a two-site Kitaev chain. We identify the conditions necessary for the emergence of PMM modes by precisely tuning the superconducting phases of the terminals and the inter-junction coupling between the 3TJJs. To validate our findings, we perform numerical simulations that account for disorder in a more general geometry and test experimentally feasible protocols based on conductance measurements to reliably detect these modes. Unlike traditional approaches that rely on magnetic fields, our design eliminates the need for such fields, potentially increasing the energy-level resolution and significantly expanding the range of compatible semiconductor materials, such as Ge-based heterostructures.