-
Excellent doctoral thesis
2023/08/06
Congratulations to Lorenzo Villa!
Lorenzo Villa successfully defended his doctoral thesis entitled “Impact of doping conditions on the Fermi level in lead-free antiferroelectrics“ in a public event on Wed, July 26th. Congratulations Lorenzo ! The next day, after an “italian” Pizza-party, he was ready to continue work his in CRC Flair !
-
Jerky dislocation motion in high-entropy alloys
2023/08/06
Members of MM division and MPIE reveal the origin
Atomistic computer simulations reproduce the jerky dislocation motion with repeated pinning in random samples without short-range order.The underlying mechanism is directly linked to local fluctuations in Peierls (force/friction) barriers, which lead to dislocation pinning points. The quantification of atomic frictional forces provides predictive design guidelines to tailor dislocation pinning in HEAs.
-
Vanadium dopants in indium sulfide
2023/08/06
Intermediate band solar cells?
Intermediate band solar cells offer a way to exceed the Shockley-Queisser limit for a cell's efficiency. To do this, an interband energy level is introduced between the valence and conduction bands. Our recent study shows that vanadium forms an intermediate empty band in alpha-indium sulfide at low concentrations.
-
Role of doping and defect quenching in antiferroelectric NaNbO3 from first principles
2022/10/07
Revealing the impact of defects on anti-ferroelectric loops
We present a method which allows to solve the charge neutrality condition while accounting for defect quenching and fixed dopant concentrations, without neglecting the dependency of their charge state on electron chemical potential and temperature.
-
Intrinsic defects in cubic NaNbO3
2022/07/28
Fermi level engineering of antiferroelectrics
Antiferroelectric NaNbO3 is a candidate material for application in high-energy density dielectric capacitors. In this context, various doping strategies have been used for installing the desired narrow double P–E loop behavior in this lead-free material. However, controlled doping requires a detailed understanding of the type and population of intrinsic defects.
-
Modelling of Quartz
2022/07/28
A machine-learned interatomic potential for silica and its relation to empirical models
Silica (SiO2) is an abundant material with a wide range of applications. Despite much progress, the atomistic modelling of the different forms of silica has remained a challenge. Here we show that by combining density-functional theory at the SCAN functional level with machine-learning-based interatomic potential fitting, a range of condensed phases of silica can be accurately described.
-
Polarons in PbTiO3 ?
2022/07/28
An Atomistic Investigation
The dissociation of short-lived excitons gives rise to free electrons and holes. If coupled with the motion of nuclei, these free charges get trapped at a lattice site and polarons form. Due to the involvement of lattice distortions in the formation of polarons, their lifetime exceeds that of excitons. In this study polaron formation and migration in PbTiO3 is addressed.
-
Revealing the impact of acceptor dopant type on the electrical conductivity of sodium bismuth titanate
2022/03/16
A combined experimental and theoretical study
Solid solutions of sodium bismuth titanate (NBT) belong to the most performant lead-free dielectric ceramics for energy storage. However, the defect chemistry of NBT is very complex, and acceptor doping can lead to an unexpected and extraordinarily high oxygen ionic conductivity. This can be attributed to a non-linear change in the formation of defect associates between acceptor and oxygen vacancy with increasing acceptor doping. Using different acceptor dopants with varying concentrations, we elucidate the interaction between acceptors and oxygen vacancies in this work. With the help of total energy calculations based on density functional theory and molecular dynamics simulations, the experimentally observed differences in conductivity can be rationalized.
-
Best poster at the MRS Autumn Meeting – The prize went to Ms. Lisette Haarmann from our division
2021/12/13
MRS 2021 Autumn Meeting 06.12.-08.12.2021
We are delighted and congratulate our colleague Lisette Haarmann on the award she received for the best poster at this event.
-
On the Origin of Zero Interface Resistance in the Li6.25 Al0.25 La3 Zr 2 O12 Li0 System
2021/12/03
An Atomistic Investigation
Understanding the nature of ion transfer at the interface between Li metal and solid electrolytes (SE) is essential for further optimization of all-solid-state Li-ion batteries. Thus, the Li transfer across the SE|Li metal interface is investigated by means of ab initio calculations based on density functional theory in this work. The aluminum-doped garnet Li 6.25 Al 0.25 La 3 Zr 2 O 12 (LLZO) is considered as a model SE due to its practical stability against Li metal. A low-energy interface model in bicrystal geometry is constructed and investigated by nudged elastic band calculations as well as ab initio molecular dynamics (AIMD) simulations.