Research and Development of WTe₂ Platform for Generation of Majorana Particles

The gapless electronic states in the topological insulators (TI) with symmetry protection are the viable platform for Majorana qubits in future fault-tolerant topological quantum computation. Among transition metal dichalcogenides, tungsten ditelluride (WTe2), which has a large spin-orbit coupling, is considered as a promising material for such TI. In this report, we introduce our recent research on WTe2 platform. We report on a heterostructure of WTe2 and superconducting material with high quality, using spontaneous formation of superconducting PdTe. We demonstrate Josephson junction devices with weak links for multi-layer WTe2. We show the electronic states of monolayer and bilayer Td-WTe2 using density functional theory. These Td-WTe2 layers can exhibit quantum spin Hall states depending on the directions of stripes and step edges, which expands the availability of WTe2. These studies deepen the process technology and material science of WTe2, which will pave the way for realizing a platform for Majorana particles.