A5089377358- Quantum and electron transport phenomena
- Advancements in Semiconductor Devices and Circuit Design
- Quantum Information and Cryptography
- Semiconductor materials and devices
- Quantum Computing Algorithms and Architecture
- Crystallography and Radiation Phenomena
- Semiconductor Quantum Structures and Devices
- Surface and Thin Film Phenomena
- Magnetic properties of thin films
IBM Research - Zurich
2022-2024
Abstract Spin qubits defined by valence band hole states are attractive for quantum information processing due to their inherent coupling electric fields, enabling fast and scalable qubit control. Heavy holes in germanium particularly promising, with recent demonstrations of high-fidelity operations. However, the mechanisms anisotropies that underlie driving decoherence remain mostly unclear. Here we report highly anisotropic heavy-hole g -tensor its dependence on revealing how originate...
Hole spins in Ge/SiGe heterostructures have emerged as an interesting qubit platform with favourable properties such fast electrical control and noise-resilient operation at sweet spots. However, commonly observed gate-induced electrostatic disorder, drifts, hysteresis hinder reproducible tune-up of SiGe-based quantum dot arrays. Here, we study Hall bar devices fabricated on present a consistent model for the origin gate its impact transport metrics charge noise. As push accumulation...
In semiconductor hole spin qubits, low magnetic field ($B$) operation extends the coherence time ($T_\mathrm{2}^*$) but proportionally reduces gate speed. contrast, singlet-triplet (ST) qubits are primarily controlled by exchange interaction ($J$) and can thus maintain high speeds even at $B$. However, a large $J$ introduces significant charge component to qubit, rendering ST more vulnerable noise when driven. Here, we demonstrate highly coherent qubit in germanium, operating both $B$ $J$....
Spin qubits defined by valence band hole states comprise an attractive candidate for quantum information processing due to their inherent coupling electric fields enabling fast and scalable qubit control. In particular, heavy holes in germanium have shown great promise, with recent demonstrations of high-fidelity operations. However, the mechanisms anisotropies that underlie driving decoherence are still mostly unclear. Here, we report on highly anisotropic heavy-hole $g$-tensor its...
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...
We discuss a custom bulk FinFET platform for implementing fast and dense hole spin qubits. Using double quantum dot with two confined holes, single- two-qubit control is demonstrated by applying electrical microwave signals to one of the gate electrodes. From these experiments we estimate that both types operations can be realized times in few nanoseconds regime. In an outlook how further scale this technology towards 2D arrays.