Impact of interface traps on charge noise, mobility and percolation density in Ge/SiGe heterostructures

• DOI: 10.48550/arxiv.2310.05902
• Publication Date: 2023-01-01
• Authors: L. Massai; Bence Hetényi; M. Mergenthaler; F. J. Schupp; L. Sommer; Stephan Paredes; Stephen W. Bedell; Patrick Harvey-Co...; G. Salis; Andreas Fuhrer; Nico W. Hendrickx
• Keywords: Condensed Matter - Mesoscale and Nanoscale Physics; Mesoscale and Nanoscale Physics (cond-mat.mes-hall); FOS: Physical sciences; 7. Clean energy

Hole spins in Ge/SiGe heterostructure quantum dots have emerged as promising qubits for computation. The strong spin-orbit coupling (SOC), characteristic of heavy-hole states Ge, enables fast and all-electrical qubit control. However, SOC also increases the susceptibility spin to charge noise. While coherence can be significantly improved by operating at sweet spots with reduced hyperfine or noise sensitivity, latter ultimately limits coherence, underlining importance understanding reducing its source. In this work, we study voltage-induced hysteresis commonly observed SiGe-based devices show that dominant fluctuators are localized semiconductor-oxide interface. By applying increasingly negative gate voltages Hall bar dot devices, investigate how hysteretic filling interface traps impacts transport metrics We find gate-induced accumulation trapping SiGe-oxide leads an increased electrostatic disorder, probed measurements, well activation low-frequency relaxation dynamics, resulting slow drifts levels. Our results highlight a conservative device tuning strategy reveal critical role SiGe heterostructures applications.