Investigating Individual Quantum Spins on Surfaces with Scanning Tunneling Microscopy
There is a strong international research effort in the area of quantum information science. Here, the concepts of quantum coherence, superposition and
entanglement of quantum states are exploited. These concepts were originally shown with photons as well as atoms and ions in vacuum traps. Over the
past two decades, many advances at studying such quantum coherence in solid-state and molecular architectures have evolved . We will begin with
a brief introduction into quantum coherence in two-level systems and investigate a conceptually simple algorithm for a quantum computation.
In the second part of this talk we will switch to my own research efforts in Scanning Tunneling Microscopy (STM). STM enables the study of surfaces
with atomic-scale spatial resolution and offers the ability to study individual atoms and molecules on surfaces. Here at Ewha, we have one of the world’s
best facilities for such studies. STM can also be used to move atoms with atomic-scale precision, which enables us to build engineered nanostructures
where each atom is in the exactly correct place.
In order to study qubits with STM, we recently learned how to combine STM with electron spin resonance [2,3]. Spin resonance gives us the means to
quantum-coherently control an individual atomic or molecular spin on a surface. Using short pulses of microwave radiation further enables us to
perform qubit rotations and learn about the quantum coherence times of our spins .
- Andreas J. Heinrich, William D. Oliver, Lieven M. K. Vandersypen, Arzhang Ardavan, Roberta Sessoli, Daniel Loss, Ania Bleszynski Jayich, Joaquin Fernandez-Rossier, Arne Laucht, Andrea Morello, “Quantum-coherent nanoscience”, Nature Nanotechnology, 16, 1318-1329 (2021).
- Susanne Baumann, William Paul, Taeyoung Choi, Christopher P. Lutz, Arzhang Ardavan, Andreas J. Heinrich, “Electron Paramagnetic Resonance of Individual Atoms on a Surface”, Science 350, 417 (2015).
- Yi Chen, Yujeong Bae, Andreas Heinrich, “Harnessing the Quantum Behavior of Spins on Surfaces”, Advanced Materials 2022, 2107534 (2022).
- Kai Yang, William Paul, Soo-Hyon Phark, Philip Willke, Yujeong Bae, Taeyoung Choi, Taner Esat, Arzhang Ardavan, Andreas J. Heinrich, and Christopher P. Lutz, “Coherent spin manipulation of individual atoms on a surface”, Science 366, 509 (2019).
Support from Institute for Basic Science (IBS-R027-D1) is gratefully acknowledged.