Quantum Properties of Individual Spin Systems on Surfaces


This team is currently the largest research area of QNS. We strive to develop high-resolution STM and AFM tools that rival the best in the world. With these tools we study the quantum properties of atoms on surfaces, with a particular focus on magnetic atoms supported on thin insulating films. Starting from the pioneering work by Heinrich and coworkers in 2004, some of us have found that the spin states can be measured with high precision. In addition, the STM can be used to move atoms and build tailored spin chains one atom at a time.

The STM offers the unique opportunity to image materials with atomic resolution, position atoms with atomic-scale precision, and measure the resulting electronic and magnetic properties with high energy resolution. A strong focus of our team lies on going even beyond those techniques. On the quest towards the quantum control of spins, it is important to be able to measure fast enough. The normal time resolution for STM is limited to a few milliseconds due to the need to measure small tunnel currents. In 2010 some of us showed that a special trick could improve this time resolution by about 1 million times. This approach offers sufficient time resolution to measure spin relaxation times of single atoms on many surfaces.

Two researchers are working full time at the IBM Research Lab in San Jose, USA, where they work hand in hand with the IBM team to explore the quantum properties of magnetic atoms on thin insulating films supported on metals. By the end of 2018, the team will have machines with similar capabilities on site. At present the experimental work is performed collaboratively with IBM and with Prof Kuk, Young at Seoul National University.

Long-Term Goals

  • Measure and control the quantum states of atoms on surfaces
  • Demonstrate the use of such atoms as qubits for quantum information protocols
  • Utilize such atoms as quantum sensors at surfaces with improved sensitivity

Near-Term Goals

  • Develop and setup state-of- the-art scanning tunneling microscopy tools at QNS
  • Perform research on the quantum states of atoms on surfaces
  • Implement fast time resolution and high-frequency measurement capabilities
  • Find new atoms and substrates with improved quantum performance


  • Andreas Heinrich
  • Taeyoung Choi
  • Soohyon Phark
  • Yujeong Bae
  • Xue Zhang
  • Yu Wang
  • Tobias Bilgeri
  • Wonjun Jang
  • Jinkyung Kim
  • Hong Bui
  • Jiyoon Hwang