Novel categories of quantum materials and electronic devices can be obtained by pipelining the evolution of electron quantum states as described by Schrödinger’s equation with inelastic processes that interrupt the coherent propagation of electrons, as now presented in Nano Express 2 014008 (2021) (open access).
These materials and devices reside in the fascinating transition regime between quantum mechanics and classical physics. The materials are designed such that a nonreciprocal unitary state evolution, achieved by a broken inversion symmetry, is interrupted by individual inelastic scattering events caused by defects. Two-terminal non-unitary quantum devices, for example, feature nonreciprocal conductance in linear response. Thus, they are exemptions to Onsager’s reciprocal relation, and they challenge the second law of thermodynamics. Materials and metamaterials featuring such functionalities may be realized by embedding such nanostructures into their unit cells.
Fig. 1: Sketch illustrating the principle of the novel quantum materials. These materials contain noncentrosymmetric unit cells with embedded inelastic scattering centers, drawn as gold dots. These centers break the phase coherence of the electron wave packets. From original publication.
Fig. 1: Sketch illustrating the principle of the novel quantum materials. These materials contain noncentrosymmetric unit cells with embedded inelastic scattering centers, drawn as gold dots. These centers break the phase coherence of the electron wave packets. From original publication.
Fig. 2: Illustration of the evolution of quantum states according to the calculational processes given by the axioms of quantum physics. If isolated from the environment, a quantum state evolves unitarily as described by Schrödinger’s equation. If coupled to the environment, the state evolution is accurately described mathematically by Born’s rule and von Neumann’s projection. From original publication.
Fig. 2: Illustration of the evolution of quantum states according to the calculational processes given by the axioms of quantum physics. If isolated from the environment, a quantum state evolves unitarily as described by Schrödinger’s equation. If coupled to the environment, the state evolution is accurately described mathematically by Born’s rule and von Neumann’s projection. From original publication.
Our team at the Max Planck Institute for Solid State Research, in collaboration with the European Synchrotron Radiation Facility (ESRF) and the Karlsruhe Institute of Technology, has uncovered a fundamental link between charge order and the pseudogap phase in the stoichiometric cuprate superconductor YBa2Cu4O8 (Y124).
Scanning tunneling microscopy visualizes signatures of p-orbital texture in the charge-density-wave state of the topological semimetal candidate CeSbTe
Spin Hall nano-oscillators convert DC to magnetic auto-oscillations in the microwave regime. Current research on these and similar devices is dedicated to creating next-generation energy-efficient hardware for communication technologies. Despite intensive research on magnetic auto-oscillations within the past decade, the nanoscale mapping of those…
Hydrogen is the most abundant element in the universe. This makes it attractive for use in sustainable technologies, such as energy storage and fuel cells, but also in novel electronic components. In contact with transition metal-oxygen compounds, it can reversibly change electrical resistance or magnetism, thereby creating functionality. However…
The world's first center for solar batteries and optoionic technologies is being established in Bavaria. The Technical University of Munich (TUM) and the Max Planck Society (MPG) have set the course for this with the support of the Bavarian Ministry of Economic Affairs. With the SolBat Center, a unique research ecosystem will be formed to research…
In search of exotic quantum magnetism on a frustrated pyrochlore lattice, scientists from the Max Planck Institute discovered an unexpected valence bond state arising from unique quenching of bond degree of freedom.
The atomic structure of some crystals, such as quartz, can be recognized with the naked eye by looking at their facets. In others, these are difficult to distinguish, even by x-ray diffraction. What happens when a second material is grown, atom by atom, on only slightly different facets of a single crystal? Are the physical properties of the…
In a collaborative effort, researchers from the Max Planck Institute for Solid State Research (MPI-FKF) have discovered a new crystal structure in La₃Ni₂O₇, a material known to exhibit high-temperature superconductivity under high pressure.