Atomically assembled quantum spin liquids


A quantum spin liquid (QSL) is a magnetic system that does not settle into a long-range ordered configuration, even at zero temperature. Instead it resides in a nontrivial quasi-disordered ground state. QSLs form ideal breeding grounds for exotic excitations, which in turn lead to fascinating phenomena. Examples include high-Tc superconductivity as well as the actively sought-after Majorana states. For decades, research in this field consisted mainly of theoretical debate. Experimental realizations of QSLs are being explored, but suitable chemical compounds are difficult to find and little can be done to tune their precise atomic geometries.

Here I propose to construct quantum spin liquids through a dramatically new approach. I intend to build lattices of magnetic atoms from the bottom up, literally atom-by-atom. Using the probe tip of a sub-Kelvin scanning tunneling microscope I will position the atoms on a surface into various one- and two-dimensional lattices, and with the same tip I will probe their spin states with atomic precision. The key indication for QSL behavior, the existence of an excitation gap due to lack of long-range order, should be readily observable through inelastic cotunneling spectroscopy. Among other things, these experiments will make it possible to carefully control and investigate various quantum phase transitions and may shed light on the dynamics of quasiparticle excitations. As an experimental approach, the technique presented here has the potential to revolutionize the field of quantum magnetism.


Scientific article

  • B. Bryant, A. Spinelli, J. J. T. Wagenaar, M. Gerrits, A. F. Otte(2013): Local control of single atom magneto-crystalline anisotropy Physical Review Letters pp. 127203-1-127203-5
  • A. Spinelli, B. Bryant, F. Delgado, J. Fern√°ndez-Rossier, A. F. Otte(2014): Imaging of spin waves in atomically designed nanomagnets Nature Materials pp. 782 - 785
  • A. Spinelli, M. P. Rebergen, A. F. Otte(2015): Atomically crafted spin lattices as model systems for quantum magnetism Journal of Physics: Condensed Matter pp. 243203 - 243203


Project number


Main applicant

Prof. dr. A.F. Otte

Affiliated with

Technische Universiteit Delft, Faculteit Technische Natuurwetenschappen, NanoScience - Kavli Institute of Nanoscience Delft

Team members

Dr. B.E.H. Bryant, Dr. J. Girovsk√Ĺ, R. Hoogerheide, T. Kool, Prof. dr. A.F. Otte, R. Toskovic MSc


01/11/2012 to 01/11/2017