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Helge Rosner
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Original 1520425773

GDCh: Claudia Felser

February 16, 2018
Structural changes have occurred with the new year in the „Gesellschaft Deutscher Chemiker“, the society for German Chemists: Professor Felser is now the new head of the research group for solid-state chemistry and material research.  [more]
Teaser 1516605880

Charge Order and Electron Localization in a Molecule-Based Solid 

January 20, 2018
Charge ordering in cationic mixed-valence compounds is of crucial importance for materials science. The prototypic example for a transition from a charge-disordered  to a charge-ordered state has been magnetite, Fe3O4, where Evert Verwey  observed a sudden jump in resistivity near -150°C. In the journal Science Advances now a research team of scientists from Germany and Slovenia reports a Verwey-type charge-ordering transition in a different class of mixed-valence compounds which is composed of negatively charged dioxygen molecules. [more]
Teaser 1516357112

Be21Pt5: a superconducting complex electron-poor intermetallic phase

January 19, 2018
The crystal structure and chemical bonding scenario of the complex intermetallic compound Be21Pt5 was solved in a joint collaboration spearheaded by scientists from the Max-Planck Institute for Chemical Physics of Solids. Be21Pt5 shows the rare case of superconductivity in a complex intermetallic compound with over 400 atoms per unit cell. Real space analysis of the calculated electron density and the electron localizability indicator (ELI) reveal structural units with collective intra-cluster interactions, termed cluster bonding, which are linked in the structure by strongly polar three-center interactions. [more]
Teaser 1515485106

Ground state wave function of the strongly correlated topological insulator SmB6

January 08, 2018
SmB6 is under focus because it may be the first topological insulator that is also strongly correlated. It is intermediate valent and a gap opens only at low temperatures due to an intricate interplay between correlation effects and hybridization, yet the surface is always conducting. The topological properties of the surface are determined by the bulk so that it is surprising that the bulk crystal-field ground state of Sm3+ was unknown until now despite many attempts by e.g. neutron scattering. Recently, scientists from the Max-Planck Institute for Chemical Physics of Solids and the University of Cologne clarified this issue by applying a new technique, namely core-level non-resonant inelastic x-ray scattering, see Sundermann et al., Phys. Rev. Letter 120, 016402 (2018). The finding that the ground state is the Γ8 quartet and not the Γ7 doublet, contradicts all existing band structure calculations and illustrates in a sobering manner the difficulties in making reliable predictions for the properties of correlated systems. [more]
Teaser 1515419323

LaNiO3: a highly metallic strongly correlated oxide with antiferromagnetic correlations

January 08, 2018
The rare earth nickelates RNiO3 with the high Ni3+ oxidation state have continued to attract enormous interest due to the famous metal-insulator transition and unusual charge and spin-order phenomena together with the prediction for multi-ferroicity and even superconductivity in thin film hetero-structures. One of the long standing puzzles is why LaNiO3 seems to be the only RNiO3 that stays metallic and paramagnetic down to lowest temperatures. Recently, the team around Alexander Komarek was able to grow centimeter-sized and impurity-free single crystals of LaNiO3 and then to unveil its true electrical and magnetic properties. The result is that the phase diagram of the RNiO3 system has to be redrawn and that theoretical concepts have to be reconsidered about how to explain the properties and the electronic structure of these high oxidation state materials. [more]
Teaser 1512391602

Pressure-induced Ferromagnetism in FeTe

December 04, 2017
The high-temperature superconductivity in iron-pnictides and –chalcogenides is based on the intricate interplay of crystal structure, electronic and magnetic states. The concerted study by scientists from different departments of the Max Planck Institute for Chemical Physics of Solids and from the Leibniz Institute for Solid State and Materials Research found for iron-telluride the remarkable result that hydrostatic pressure leads to the emergence of ferromagnetic order in a peculiar way. [more]
Teaser 1511777954

Ultraclean metal-like conductivity in semimetallic WP2

November 27, 2017
Ultraclean metals show high conductivity with a high number of charge carriers, whereas semiconductors and semimetals with low charge carriers normally show a low conductivity. This scenario in semimetals can be changed if one can protect the carriers from scattering.  [more]
Teaser 1511528195

The Iron Age: about the understanding of the new iron-based high-temperature superconductors and related compounds

November 24, 2017
In the new iron-based superconductors (FeSC), superconductivity occurs close to an antiferromagnetic phase. This indicates that correlation effects may be important in these materials. Theoretical calculations predict that different from cuprates, besides the on-site Coulomb interaction also the on-site Hund exchange interaction plays an important role in the correlation effects of FeSCs. This would mean that a completely new state of correlated matter has appeared which has been termed “Hund’s metal”. [more]
Teaser 1510315424

Thermodynamic signatures of field-induced phase transitions in graphite

November 10, 2017
Graphite is a model system for the study of electrons in the so-called magnetic quantum limit. This quantum limit is attained when the magnetic field is strong enough to confine the charge carriers to their lowest Landau levels. It is expected that the model of the free electron gas fails beyond this limit since here electron interactions may play a significant role in determining the electronic ground state. Indeed, our thermodynamic studies in high magnetic field revealed that even electron-lattice interaction has to be taken into account in addition to electron-electron interaction.    [more]
Teaser 1510308474

New features in multipolar heavy-fermion materials

November 10, 2017
The simple cubic structure of CeB6 does not change while intricate multipolar phenomena are developed upon a non-magnetic La substitution. However, phase diagrams of Ce1-xLaxB6 have been elusive for the last decades. Recently, detailed phase transitions in Ce1-xLaxB6 have been revealed by scientists of MPI-CPfS, TU-Dresden, and I. M. Frantsevich Institute. In addition, a simple feature which is likely to be observed in a multipolar heavy-fermion system has been found.  [more]
Teaser 1509706517

Robust Bain distortion in the premartensite phase of a platinum-substituted Ni2MnGa magnetic shape memory alloy

October 23, 2017
The premartensite phase of shape memory and magnetic shape memory alloys is believed to be a precursor state of the martensite phase with preserved austenite phase symmetry. The thermodynamic stability of the premartensite phase and its relation to the martensitic phase is still an unresolved issue, even though it is critical to the understanding of the functional properties of magnetic shape memory alloys. [more]
Teaser 1508741912

Dr. Steffen Wirth zum Fellow der American Physical Society (APS) gewählt

October 20, 2017
Steffen Wirth erhält die Fellowship für „seine grundlegenden Beiträge zu unserem Verständnis von stark korrelierten Elektronensystemen, insbesondere bei reduzierten Längenskalen, einschließlich des Kondo-Effekts und magnetischer Wechselwirkungen", wie es in der Ernennungsurkunde heißt.  [more]
Teaser 1506601088

Electrons with different spin maximally split 

September 28, 2017
The surfaces of materials can host unique electronic properties, where the electrons behave very differently from the interior. In particular, the intrinsically broken symmetries of the surface compared with the bulk of the sample allows for a separation of energy states according to their spin. This effect could be utilised in novel electronic devices which operate with both the charge and spin of electrons- but it is first necessary to understand how to maximise the magnitude of the effect. [more]
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Quantum Tricritical Points

September 20, 2017
The concept of 'quantum critical point', the zero temperature point of a line of 2nd order phase transitions, is rather modern: It is nowadays strongly investigated mainly in connection with unconventional superconductivity. Recent experimental and theoretical works have shown that some metals show competing ferro- and antiferromagnetic order at very low temperature. This allows for the possibility of multiple critical points and thus, at T=0, for quantum tricritical points. [more]
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New insights into heat conduction in solids

September 11, 2017
Phonons passing a thermal insulator generally have a short life time. The investigation of the clathrate I phase Ba7.81Au5.33Ge40.67 shows now a completely different picture. [more]
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Bit data goes anti-skyrmions

September 01, 2017
Today’s world, rapidly changing because of “big data”, is encapsulated in trillions of tiny magnetic objects – magnetic bits – each of which stores one bit of data in magnetic disk drives.   A group of scientists from the Max Planck Institutes in Halle and Dresden have discovered a new kind of magnetic nano-object in a novel material that could serve as a magnetic bit with cloaking properties to make a magnetic disk drive with no moving parts – a Racetrack Memory – a reality in the near future. [more]
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Dr. Enke Liu honored with National Science Fund for Excellent Young Scholars

September 01, 2017
The National Natural Science Foundation of China honors Dr. Enke Liu, a Humboldt research fellow of the Alexander von Humboldt Foundation, with the 2017 National Science Fund for Excellent Young Scholars for his great contribution to magnetic phase transitions. This scholarship serves as a substantial bolster to the young talents in China. [more]
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Electrons choose a direction

August 22, 2017
The group “Micro Structured Quantum Matters” at MPI-CPfS develops microscopic electric conducting paths made of quantum materials to understand their physical properties and to test possible applications in new types of electronics. In cooperation with US scientists, they succeeded in showing a rare state in microchips in which electrons move together. That state is called “electronic nematicity”. It occurs in high magnetic fields in a layered metal made of cerium, rhodium and indium, called CeRhIn5. In an article published in the journal “Nature”, the scientists point to a new approach of understanding the link between electronic nematicity and superconductivity. Electrons move together in the superconductivity as well and links between the two phenomena were assumed for a long time. [more]
Teaser 1500557051

Topological Quantum Chemistry

July 20, 2017
Researchers find path to discovering new topological materials, holding promise for technological applications. [more]
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IBM Scientists Observe Elusive Gravitational Effect in Solid-State Physics

July 19, 2017
Previously thought to only occur in the early stages of the universe and within neutron stars and black holes [more]
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