Hole mobility in compressively strained germanium on silicon exceeds 7 × 106 cm2V-1s−1

The concurrent achievement of the record-low resistance charge transport and compatibility with spin qubit technology in solid-state materials is a critical milestone for advancing high-speed, energy-efficient classical and quantum electronics technologies. Here, we demonstrate that holes, the positively charged counterparts of electrons, can propagate with exceptional ease in a nanometres-thin compressively strained germanium layer epitaxially grown on a silicon substrate. Through precise material engineering, we achieve a record-breaking hole mobility of 7.15 × 10 6 cm 2 V -1 s −1 at a density of 1.7 × 10 11 cm −2 , establishing a new benchmark for hole transport in group-IV semiconductor materials, importantly, epitaxially grown on a silicon substrate. Our work outlines a design strategy for realising an ultra-clean, low-dimensional system that confines highly mobile holes within a quantum well, while maintaining excellent electrostatic tunability. Crucially, the observed high hole mobility is achieved in gated Hall-bar devices, demonstrating their practical viability for scalable cryogenic classical and quantum electronics applications. These findings unlock new opportunities for a high-performance semiconductor platform capable of underpinning the next generation of quantum information processing, cloud data centres, AI-driven technologies and energy-efficient electronics.