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Invited Lecture

In operando photoemission spectroscopy of PMN-PT interfaces

Thursday (08.06.2017)
00:20 - 01:00 Förde II + III
Part of:
Line-Up:
12:20 Invited Lecture Similarities and differences between magnetic hysteresis and hysteresis in phase transformations 0 Richard James
13:00 Invited Lecture Discovery and Design of Multifunctional Materials using Combinatorial and High-Throughput Experimentation 1 Prof. Dr. Alfred Ludwig
15:10 Invited Lecture Tuning Mechanical Properties of Spider Cuticle by its Composition and by Structural Gradients 0 Dr. Yael Politi
15:50 Invited Lecture Surfaces and Gels for controlling Calcium Phosphate Deposition 0 Prof. Dr. Andreas Taubert
17:40 Invited Lecture Probing the Structure and Dynamic Behaviors of Ferroelectrics by Electron Microscopy with Atomic Resolution in Real Time 0 Prof. Xiaoqing Pan
18:20 Invited Lecture Magnetoelectric Composites for Energy Harvesting 1 Robert E. Hord, Jr. Professor Shashank Priya
19:40 Invited Lecture Declamping in Lead Magnesium Niobate – Lead Titanate Films 1 Prof. Susan Trolier-McKinstry
20:20 Invited Lecture Integrated Magnetics and Multiferroics for Compact and Power Efficient Sensing, Power, RF, Microwave and mm-Wave Electronics 0 Prof. Nian X. Sun
21:00 Invited Lecture From Maxwell’s displacement current to nanogenerator driven self-powered systems and blue energy 0 Prof. Zhong Lin Wang
21:40 Invited Lecture Magnetoelectric Composites: from Sensors to Sensor Systems 0 Prof. Dr.-Ing. Gerhard Schmidt
22:20 Invited Lecture Metal–insulator transition in vanadium oxides films and its applications 1 Dr. Keisuke Shibuya
00:20 Invited Lecture In operando photoemission spectroscopy of PMN-PT interfaces 0 Prof. Dr. Kai Rossnagel
08:30 Invited Lecture Titanium-Tantalum High Temperature Shape Memory Spring Actuators 1 Prof. Dr. Gunther Eggeler
09:10 Invited Lecture Vortex-antivortex topological structures in multiferroic tunnel junctions 1 Dr. Ana Sanchez
09:50 Invited Lecture Artificial Ferroic Systems 1 Prof. Laura Heyderman
17:40 Invited Lecture Biomimicry at the molecular level: Molecularly imprinted polymers as synthetic antibody mimics 0 Karsten Haupt
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External

control of the electron flow across interfaces is what makes electronic

devices. The relaxor ferroelectric 0.72PbMg1/3Nb2/3O3-0.28TiO3

(PMN-PT) provides a fertile platform for the study of novel bias-dependent

electrical polarization and lattice strain effects on electronic behavior at

interfaces. For example, at the interface to a metal the fundamental electrical

interface property, the Schottky barrier height, becomes dependent on the

magnitude and direction of the polarization, whereas at the interface to a strongly

correlated material the field-induced strain may drive a metal-to-insulator

transition. A major challenge, however, is to directly probe such modifications

of the interfacial electronic structure in device-like structures.

 

Here, we demonstrate

that hard x-ray photoelectron spectroscopy (HAXPES) is a powerful tool to image

the electronic energy-level alignment at buried interfaces in operando as a function of electrical bias. For the cases of metal/PMN-PT

and VO2/PMN-PT interfaces, we comprehensively track the bias

dependence of the substrate and electrode core levels as well as of the valence

density of states. These spectroscopic data provide an intriguingly direct view

on how key electrical parameters such as the Schottky barrier height and the

density of states at the Fermi level can be tuned in situ by electrical polarization and field-induced lattice strain.

The findings may in particular open novel ways to control the conductivity

across metal-ferroelectric interfaces and of thin VO2 layers,

respectively.

 

To further

illustrate the power of the experimental technique, we will finally present the

upcoming fascinating possibility of performing femtosecond time-resolved HAXPES

measurements at the European XFEL, which may enable us to film the electron

dynamics at buried interfaces on fundamental time scales. 

 

 

Speaker:
Prof. Dr. Kai Rossnagel
Christian-Albrechts-Universität zu Kiel