Abstract Scope |
Tunneling is a hallmark quantum mechanical behavior intrinsically related to superposition. Whereas tunneling has been proposed as the origin of glass-like thermal conductivity in amorphous materials, a clear identification of these tunneling states is lacking. In contrast, tunneling in crystalline materials is often restricted to a hydrogen or a small fraction of impurity atoms. Here we will report on the tunneling of a heavy atom in the framework of BaTiS3[1] and Eu8Ga16Ge30[2], two crystalline materials with ultra-low glass-like thermal conductivity at low temperature. In both materials, clear tunneling lines observed by spectroscopy or scattering enable insight in the ground state and transport of the material.
All collaborators, support from DOE Office of Basic Energy Science, and the neutron sources at ORNL are gratefully acknowledged.
[1] Sun et al., Nature Comm. 11, 6039 (2020).
[2] Hermann et al., Phys. Rev. Lett. 97, 017401 (2006). |