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Your search keyword '"Deringer, Volker L."' showing total 11 results
Start Over Author "Deringer, Volker L." Publication Year Range Last 50 years Journal chemistry of materials
11 results on '"Deringer, Volker L."'

8. Chemical Tuning of Carrier Type and Concentration in a Homologous Series of Crystalline Chalcogenides

Author

Schäfer, Tobias, Konze, Philipp M., Huyeng, Jonas D., Deringer, Volker L., Lesieur, Thibault, Müller, Paul, Morgenstern, Markus, Dronskowski, Richard, and Wuttig, Matthias

Abstract

Tellurium-based phase-change materials (PCMs) enable applications from optical and electronic data storage to thermoelectrics and plasmonics, which all demand precise control of electronic properties. These materials contain an unusually large number of vacancies: “stoichiometric” ones that stem from the chemical composition and “excess” vacancies that act like classical dopants. Here we show how both types of vacancies can be controlled independentlyin the solid solution Sn(Sb1–xBix)2Te4. We vary xin small steps over the entire compositional range and show that this has a profound effect on the material’s electronic nature: remarkably, we observe a change from p- to n-type conduction at x≈ 0.7, solely controlled by composition. Our findings lead to a new compositionally (that is, chemically) tunable materials platform that enables precise control of electrical properties.

Published
2024
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11. Mechanismsof Atomic Motion Through Crystalline GeTe.

Author

Deringer, Volker L., Lumeij, Marck, Stoffel, Ralf P., and Dronskowski, Richard

Subjects
*GERMANIUM telluride, *CRYSTAL structure, *PHASE change materials, *VACANCIES in crystals, *ENERGY bands, *DENSITY functional theory, *ELECTRONIC structure
Abstract

Germaniumtelluride (GeTe) is an iconic functional material, bothin itself and as the parent compound for a range of ternary phase-changedata-storage alloys. Long taken to be a “simple” ABcompound, crystalline GeTe is today known to contain a large numberof germanium vacancies which directly affect the material’smacroscopic properties. Here, we use atomistic simulations to elucidatelocal mechanisms behind the motion of Ge atoms (and thus, vacancydiffusion) in crystalline GeTe. Transition pathways are computed usingthe nudged elastic band (NEB) approach at the gradient-corrected levelof density-functional theory (GGA-DFT), both for the idealized rhombohedral(R3m) crystal and a number of defectiveconfigurations. Besides obvious structural arguments (i.e., beyonda simple rigid-sphere model), the diffusion barriers show a delicatedependence on the material’s electronic structure. The latteris controlled by vacancy formation, Sb adatoms, and charge injection,all of which is discussed in a unified framework. [ABSTRACT FROM AUTHOR]

Published
2013
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