@article{Bui2024,

title = {All-Electrical Driving and Probing of Dressed States in a Single Spin},

author = {Hong T Bui and Christoph Wolf and Yu Wang and Masahiro Haze and Arzhang Ardavan and Andreas J Heinrich and Soo Hyon Phark},

doi = {10.1021/acsnano.4c00196},

issn = {1936086X},

year  = {2024},

date = {2024-05-01},

urldate = {2024-05-01},

journal = {ACS Nano},

volume = {18},

number = {19},

pages = {12187–12193},

publisher = {American Chemical Society (ACS)},

abstract = {The subnanometer distance between tip and sample in a scanning tunneling microscope (STM) enables the application of very large electric fields with a strength as high as ∼1 GV/m. This has allowed for efficient electrical driving of Rabi oscillations of a single spin on a surface at a moderate radiofrequency (RF) voltage on the order of tens of millivolts. Here, we demonstrate the creation of dressed states of a single electron spin localized in the STM tunnel junction by using resonant RF driving voltages. The read-out of these dressed states was achieved all electrically by a weakly coupled probe spin. Our work highlights the strength of the atomic-scale geometry inherent to the STM that facilitates the creation and control of dressed states, which are promising for the design of atomic scale quantum devices using individual spins on surfaces.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wang2023a,

title = {An atomic-scale multi-qubit platform},

author = {Yu Wang and Yi Chen and Hong T Bui and Christoph Wolf and Masahiro Haze and Cristina Mier and Jinkyung Kim and Deung-Jang Choi and Christopher P Lutz and Yujeong Bae and Soo-Hyon Phark and Andreas J Heinrich},

url = {https://www.science.org/doi/10.1126/science.ade5050},

doi = {10.1126/science.ade5050},

issn = {0036-8075},

year  = {2023},

date = {2023-10-01},

urldate = {2023-10-01},

journal = {Science},

volume = {382},

number = {6666},

pages = {87–92},

abstract = {Individual electron spins in solids are promising candidates for quantum science and technology, where bottom-up assembly of a quantum device with atomically precise couplings has long been envisioned. Here, we realized atom-by-atom construction, coherent operations, and readout of coupled electron-spin qubits using a scanning tunneling microscope. To enable the coherent control of “remote” qubits that are outside of the tunnel junction, we complemented each electron spin with a local magnetic field gradient from a nearby single-atom magnet. Readout was achieved by using a sensor qubit in the tunnel junction and implementing pulsed double electron spin resonance. Fast single-, two-, and three-qubit operations were thereby demonstrated in an all-electrical fashion. Our angstrom-scale qubit platform may enable quantum functionalities using electron spin arrays built atom by atom on a surface.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Phark2023,

title = {Double-Resonance Spectroscopy of Coupled Electron Spins on a Surface},

author = {Soo Hyon Phark and Yi Chen and Hong T Bui and Yu Wang and Masahiro Haze and Jinkyung Kim and Yujeong Bae and Andreas J Heinrich and Christoph Wolf},

url = {https://pubs.acs.org/doi/10.1021/acsnano.3c04754},

doi = {10.1021/acsnano.3c04754},

issn = {1936086X},

year  = {2023},

date = {2023-07-01},

urldate = {2023-07-01},

journal = {ACS Nano},

volume = {17},

number = {14},

pages = {14144–14151},

abstract = {Scanning-tunneling microscopy (STM) combined with electron spin resonance (ESR) has enabled single-spin spectroscopy with nanoelectronvolt energy resolution and angstrom-scale spatial resolution, which allows quantum sensing and magnetic resonance imaging at the atomic scale. Extending this spectroscopic tool to a study of multiple spins, however, is nontrivial due to the extreme locality of the STM tunnel junction. Here we demonstrate double electron-electron spin resonance spectroscopy in an STM for two coupled atomic spins by simultaneously and independently driving them using two continuous-wave radio frequency voltages. We show the ability to drive and detect the resonance of a spin that is remote from the tunnel junction while read-out is achieved via the spin in the tunnel junction. Open quantum system simulations for two coupled spins reproduce all double-resonance spectra and further reveal a relaxation time of the remote spin that is longer by an order of magnitude than that of the local spin in the tunnel junction. Our technique can be applied to quantum-coherent multi-spin sensing, simulation, and manipulation in engineered spin structures on surfaces.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Zhang2022,

title = {Electron spin resonance of single iron phthalocyanine molecules and role of their non-localized spins in magnetic interactions},

author = {Xue Zhang and Christoph Wolf and Yu Wang and Hervé Aubin and Tobias Bilgeri and Philip Willke and Andreas J. Heinrich and Taeyoung Choi},

url = {https://www.nature.com/articles/s41557-021-00827-7},

doi = {10.1038/s41557-021-00827-7},

issn = {1755-4330},

year  = {2022},

date = {2022-01-01},

urldate = {2022-01-01},

journal = {Nature Chemistry},

volume = {14},

number = {1},

pages = {59–65},

publisher = {Springer Science and Business Media LLC},

abstract = {Electron spin resonance (ESR) spectroscopy is a crucial tool, through spin labelling, in investigations of the chemical structure of materials and of the electronic structure of materials associated with unpaired spins. ESR spectra measured in molecular systems, however, are established on large ensembles of spins and usually require a complicated structural analysis. Recently, the combination of scanning tunnelling microscopy with ESR has proved to be a powerful tool to image and coherently control individual atomic spins on surfaces. Here we extend this technique to single coordination complexes-iron phthalocyanines (FePc)-and investigate the magnetic interactions between their molecular spin with either another molecular spin (in FePc-FePc dimers) or an atomic spin (in FePc-Ti pairs). We show that the molecular spin density of FePc is both localized at the central Fe atom and also distributed to the ligands (Pc), which yields a strongly molecular-geometry-dependent exchange coupling.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}