Imaging fractionalized excitations and their impact on magnetic interactions in two-dimensional quantum spin liquids
Final Report Abstract
Quantum spin liquids are a special class of spin systems in which competing interactions lead to a large ground state degeneracy instead of quasi-classical magnetic ordering as in most materials. These systems have several exotic properties, such as the emergence of fractionalized excitations like spinons or Majorana quasiparticles. This can lead to new effects that may be exploited in spintronics or in quantum information applications. We have proposed to conduct scanning tunnelling microscopy experiments on two-dimensional materials that are promising candidates for hosting a quantum spin liquid ground state. These investigations are expected to provide additional evidence for a quantum spin liquid state in these materials and even to experimentally demonstrate novel physical effects that have never been observed before, like the mediation of magnetic interactions via fractional spinons, or the localization of Majorana quasiparticles in 2D device heterostructures. As argued in my proposal, these heterostructures can only be studied by Crommie and his collaborators as of today, for no other group has solved the problem of electrically contacting semiconducting 2D materials for cryogenic STM characterization. Most of this is still work in progress. Namely, we have implemented spin-polarized scanning tunneling microscopy in a new lab in Prof. Crommie’s group, which is a requirement for the proposed experiments. Moreover, we have successfully started to study 2D device heterostructures in this lab, something only a few groups in the world are able to do. This paves the way for the studies of quantum spin liquid materials as proposed that will be carried out by other members of the Crommie group in the near future.
