All-electric control of single atom spin states

N. Tobias Jacobson, Patrick Harvey-Collard, Andrew Baczewski +5 more

Rostyslav Savytskyy, Tim Botzem, Irene Fernández de Fuentes +9 more

The spins of atoms and atom-like systems are among the most coherent objects in which to store quantum information. However, the need to address them using oscillating magnetic fields hinders their integration with quantum electronic devices. Here, we circumvent this hurdle by operating a single-atom "flip-flop" qubit in silicon, where quantum information is encoded in the electron-nuclear states of a phosphorus donor. The qubit is controlled using local electric fields at microwave frequencies, produced within a metal-oxide-semiconductor device. The electrical drive is mediated by the modulation of the electron-nuclear hyperfine coupling, a method that can be extended to many other atomic and molecular systems and to the hyperpolarization of nuclear spin ensembles. These results pave the way to the construction of solid-state quantum processors where dense arrays of atoms can be controlled using only local electric fields.

Jianpei Geng

Yaowu Liu, Dasom Choi, Stefano Reale +8 more

Electrical control of single spin qubits is a major frontier for nanoscale, high-speed, and scalable quantum devices. Yet, extending it to highly shielded rare-earth 4f electrons remains an experimental challenge across solid-state platforms. Here we demonstrate all-electrical coherent control of a single Er electron spin, which is exchange-coupled to a nearby Ti atom. Scanning tunneling microscopy-based electron spin resonance with three-dimensional magnetic-field control enables comprehensive mapping of the resonance and Rabi frequencies, revealing pronounced anisotropies in both the Er g-tensor and the Er-Ti exchange interaction. The electrical modulation of the anisotropic Er-Ti coupling results in an efficient drive of the Er spin, allowing us to achieve near-gigahertz Rabi frequencies - a ten-fold improvement over the present record for rare-earth spin qubits. By establishing anisotropic exchange as a general resource for electrically accessing shielded rare-earth spins, our results open a new route to ultrafast and local control of rare-earth spins in solid-state quantum devices.

Dimitrios Charalambidis, Natalia E. Karapanagioti, D. Xenakis +8 more

Johannes K. Krondorfer, Sebastian Pucher, Matthias Diez +2 more

Abstract The precise control of nuclear spin states is crucial for a wide range of quantum technology applications. Here, we propose a fast and robust single-qubit gate in 87 Sr utilizing the concept of optical nuclear electric resonance (ONER). ONER exploits the interaction between the quadrupole moment of a nucleus and the electric field gradient generated by its electronic environment, enabling spin level transitions via amplitude-modulated laser light. We investigate the hyperfine structure of the 5s 2 1 S 0 → 5s5p 3 P 1 optical transition in neutral 87 Sr and identify the magnetic field strengths and laser parameters necessary to drive spin transitions between the m I = − 9 / 2 and m I = − 5 / 2 hyperfine levels in the ground state. Our simulations show that ONER could enable faster spin operations compared to the state-of-the-art oscillations in this ‘atomic qubit’. Moreover, we show that spin-flip operations exceeding 99.9% fidelity can be performed even in the presence of typical noise sources. These results pave the way for significant advances in nuclear spin control, opening new possibilities for quantum memories and other quantum technologies.