Solid, liquid and gaseous - these are the three states of matter, we are familiar with. When we consider our everyday experience, the idea, that a homogeneous material could exhibit properties of two of these states simultaneously, seems implausible. Even more difficult to imagine is a compound, that is solid and at the same time superfluid, i.e. without any viscosity. In such a supersolid the atoms are arranged in a crystalline pattern, while at the same time behaving like a superfluid, in which particles move without friction. Nevertheless, such a complex state of matter has been proposed theoretically for more than 50 years.
At the same time as two other international research groups, that used laser cooling of atoms in "atomic traps" for their experiments, physicists from Augsburg and Dresden now report on the experimental realization of supersolidity in spin systems at high magnetic fields in the renowned journal "Science Advances". In 1970 Antony Legget posed the question "Can a Solid be Superfluid”? In 2017 it seems that this question can clearly be answered with "Yes".
A quantumfluid of fluctuating spin-spirals in MnSc2S4
An unconventional and exotic magnetic ground state has been detected in cooperation with an international group of scientists: Neutron-scattering experiments at the Heinz-Maier-Leibnitz Zentrum in Munich and at the Paul Scherrer Institut in Villingen (CH) provide experimental evidence, that at low temperatures the spins in MnSc2S4 do not exhibit long-range magnetic order, but rather form a quantum state of fluctuating spin spirals. These results have recently been published in "Nature Physics".
How does the melt become glass?
In a recently published paper in "Science", together with scientists from the University of Paris, we solve a long-standing controversy: We provide evidence that the solidification of glass is due to a phase transition, even though of unconventional nature, accompanied by an increase of molecular cooperativity.
Our group covers a broad field of investigations in condensed matter physics. We focus on new materials for future electronics, on unconventional ground states, superconductors, the dynamics of disordered matter and biological materials.
Aside of a large number of sample characterization methods, a strong point of our group is the combination of a variety of spectroscopic methods enabling deep insight into the microscopic properties of condensed matter. This not only includes dielectric, THz, and optical spectroscopy but also electron and nuclear magnetic resonance techniques.