Novel low dimensional mixed valent transition metal chalcogenides discovered by exploratory synthesis

6^th International Conference and Exhibition on Materials Science and Chemistry

May 17-18, 2018 | Rome, Italy

Mihai I Sturza, Alexander J E Rettie, Daniel Bugaris, Fei Han, Christos Malliakas, Saicharan Aswartham, Duck Young Chung, Mercouri Kanatzidis, and Bernd Buchner

FW Dresden - Institute for Solid State Research, Germany
Argonne National Laboratory, USA
Northwestern University, USA

Posters & Accepted Abstracts: J Material Sci Eng

Abstract :

The class of transition-metal chalcogenides that exhibits mixed valency has been of continuing interest for several decades. The emergence of superconductivity with a superconducting transition temperature (Tc<30 K) in mixed-valence AxFe2� ySe2 (A=K, Rb, Cs, and Tl) phases has further increased interest in the chemistry and physics of complex ternary transitionmetal chalcogenides. Copper chalcogenide materials are of considerable scientific interest because of their rich structural and compositional diversity, mixed valency, propensity for phase transitions, charge-density waves, potential for ionic mobility, as well as applications such as high performance photovoltaic cells. New results from the chemistry of the A/Cu/Q (A=Na, K, Ba; Q=S, Se) system will be reported. The synthesis, crystal structure, and properties of new layered copper chalcogenide compounds, which are mixed-valent will be presented. Single crystals were grown by the reaction of Cu metal in a molten alkali/ alkaline-earth metal/polysulfide/polyselenide/flux. Single crystal x-ray diffraction measurements performed on several crystals showed a high quality of the crystals, proven by the good internal consistency of the data collected using the full-sphere mode and an extremely low R factor. Electronic band structure calculations and physical property measurements reveal p-type metallic behavior, with moderately high electrical conductivity and hole carrier mobilities. Recent Publications 1. A J E Rettie, M Sturza, C D Malliakas, A S Botana, M R Norman, D Y Chung and M G Kanatzidis (2017) Copper vacancies and heavy holes in the two-dimensional semiconductor KCu3-xSe2. Chem. Mater. 29(14):6114�6121. 2. M Sturza, D E Bugaris, C D Malliakas, F Han, D Y Chung and M G Kanatzidis (2016) Mixed valent NaCu4Se3: A twodimensional. Inorg. Chem. 55(10):48844890. 3. H J Grafe, S Nishimoto, M Iakovleva, E Vavilova, A Alfonsov, M I Sturza, S Wurmehl, H Nojiri, H Rosner, J Richter, U K Ro��ler, S L Drechsler, V Kataev and B Buchner (2017) Evidence for a magnetic field-induced hidden spin nematic phase in the frustrated and anisotropic spin-chain cuprate LiCuSbO4. Scientific Reports 7:6720. 4. M Sturza, J M Allred, C D Malliakas, D E Bugaris, F Han, D Y Chung and M G Kanatzidis (2015) Tuning the magnetic properties of new layered iron chalcogenides (BaF)2Fe2�xQ3 (Q=S, Se) by changing the defect concentration on the iron sublatice. Chem. Mater. 27:3280�3290. 5. M Sturza, C D Malliakas, D E Bugaris, F Han, D Y Chung and M G Kanatzidis (2014) NaCu6Se4: A layered compound with mixed valency and metallic properties, Inorg. Chem. 53(22):12191-12198.

Biography :

Mihai I Sturza has his expertise in synthesis and crystal structure characterization of novel inorganic compounds. The main aim of his work is to synthesize new inorganic compounds (new oxides, oxo-halides, pnictides, chalcogenides, intermetallics, etc.) and to correlate their chemical and physical properties to their compositions and crystal structures. His research at IFW involves searching for novel low-dimensional materials with interesting electronic properties emerging from a competition between different electronic states or a suppression of the electronic order (charge, orbital or spin).

Email:m.i.sturza@ifw-dresden.de