Amalgams of less noble metals as model systems for polar intermetallic phases

• Applicant: Privatdozent Dr. Constantin Hoch
• Subject Area: Solid State and Surface Chemistry, Material Synthesis
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 429690805

Polar intermetallic phases are metallic compounds in which electric, magnetic or Coulombic dipoles from electronegativity differences are in interplay with the conduction electrons. They are the topic of intensive studies because this interplay leads to combinations of at the first glance irreconcilable properties, such as e.g. ferroelectricity and metallic conductivity in one material. The impact of polar intermetallic phases is porven by the increasing number of studies and first applications, e.g. in modern data storage devices. The underlying principles necessary for a targetted creation of new properties and new property combinations still aren't understood. Studying appropriate model systems may help a lot in systematically revealing the relevant structure property relations in polar intermetallic phases. Amalgams of the less noble metals have proven suitable as model systems over the last years, especially the mercury-richest members of this class of intermetallic compounds.The number of well-studied compunds in this fied still is too small as to give a clear picture over the general trends and rules. This project therefore deals with synthesis and structural and physical characterisation of new amalgams of less noble metals. New binaries, such as beryllium amalgams, as well as ternary amalgams with two different less noble metals shall be targetted in the first systematic study on Hg-rich amalgams. Chemical synthesis of gam-scaled samples and of single crystals for structural elucidation are the base for comprehensive characterisations by measurement of electric conductivity, susceptibility, as well as thermoanalytical and thermoelectrical behaviour. They will be combined with quantum-chemical calculations of the electronic structure and with NMR-spectroscopic determination of the Knight shift. This project is meant to increase knowledge on the interplay of conduction electrons with internal dipole moments in a metallic compound, in order to enable purposeful synthesis of polar intermetallic phases with combinations of properties suitable for application in new electronic materials and devices. Our group and our coworkers have shown with a number of preliminary studies on this topic to be capable of auspiciously conducting this project.

• DFG Programme: Research Grants