TY - JOUR AB - Structural strain severely impacts material properties, such as the linear and nonlinear optical response. Moreover, strain plays a key role, e.g., in the physics of ferroelectrics and, in particular, of their domain walls. μ-Raman spectroscopy is a well-suited technique for the investigation of such strain effects as it allows to measure the lattice dynamics locally. However, quantifying and reconstructing strain fields from Raman maps requires knowledge on the strain dependence of phonon frequencies. In this paper, we have analyzed both theoretically and experimentally the phonon frequencies in the widely used ferroelectrics lithium niobate and lithium tantalate as a function of uniaxial strain via density functional theory and μ-Raman spectroscopy. Overall, we find a good agreement between our ab initio models and the experimental data performed with a stress cell. The majority of phonons show an increase in frequency under compressive strain, whereas the opposite is observed for tensile strains. Moreover, for E-type phonons, we observe the lifting of degeneracy already at moderate strain fields (i.e., at ±0.2%) along the x and y directions. This paper, hence, allows for the systematic analysis of three-dimensional strains in modern-type bulk and thin-film devices assembled from lithium niobate and tantalate. AU - Singh, Ekta AU - Pionteck, Mike N. AU - Reitzig, Sven AU - Lange, Michael AU - Rüsing, Michael AU - Eng, Lukas M. AU - Sanna, Simone ID - 47993 IS - 2 JF - Physical Review Materials KW - Physics and Astronomy (miscellaneous) KW - General Materials Science SN - 2475-9953 TI - Vibrational properties of LiNbO3 and LiTaO3 under uniaxial stress VL - 7 ER - TY - JOUR AB - Coherent nonlinear optical μ-spectroscopy is a frequently used tool in modern material science as it is sensitive to many different local observables, which comprise, among others, crystal symmetry and vibrational properties. The richness in information, however, may come with challenges in data interpretation, as one has to disentangle the many different effects like multiple reflections, phase jumps at interfaces, or the influence of the Guoy-phase. In order to facilitate interpretation, the work presented here proposes an easy-to-use semi-analytical modeling Ansatz, which bases upon known analytical solutions using Gaussian beams. Specifically, we apply this Ansatz to compute nonlinear optical responses of (thin film) optical materials. We try to conserve the meaning of intuitive parameters like the Gouy-phase and the nonlinear coherent interaction length. In particular, the concept of coherence length is extended, which is a must when using focal beams. The model is subsequently applied to exemplary cases of second- and third-harmonic generation. We observe a very good agreement with experimental data, and furthermore, despite the constraints and limits of the analytical Ansatz, our model performs similarly well as when using more rigorous simulations. However, it outperforms the latter in terms of computational power, requiring more than three orders less computational time and less performant computer systems. AU - Spychala, Kai J. AU - Amber, Zeeshan H. AU - Eng, Lukas M. AU - Rüsing, Michael ID - 47994 IS - 12 JF - Journal of Applied Physics KW - General Physics and Astronomy SN - 0021-8979 TI - Modeling nonlinear optical interactions of focused beams in bulk crystals and thin films: A phenomenological approach VL - 133 ER - TY - JOUR AU - Liu, Ping AU - Schumann, Nils AU - Abele, Fabian AU - Ren, Fazheng AU - Hanke, Marcel AU - Xin, Yang AU - Hartmann, Andreas AU - Schlierf, Michael AU - Keller, Adrian AU - Lin, Weilin AU - Zhang, Yixin ID - 48013 JF - ACS Applied Nano Materials KW - General Materials Science SN - 2574-0970 TI - Thermophoretic Analysis of Biomolecules across the Nanoscales in Self-Assembled Polymeric Matrices ER - TY - CHAP AU - Schuster, Britt-Marie AU - Haaf, Susanne ED - Haaf, Susanne ED - Schuster, Britt-Marie ID - 48025 T2 - Historische Textmuster im Wandel. Neue Wege zu Ihrer Erschließung TI - Fünf Thesen zur Untersuchung des Textsortenwandels VL - 331 ER - TY - CHAP AU - Schuster, Britt-Marie AU - Thielert, Frauke AU - Haaf, Susanne ED - Haaf, Susanne ED - Schuster, Britt-Marie ID - 48029 T2 - Historische Textmuster im Wandel. Neue Wege zu ihrer Erschließung TI - Fragen stellen in Pressetextsorten ER - TY - CHAP AU - Schuster, Britt-Marie ED - Markewitz, Friedrich ED - Scholl, Stefan ED - Schubert, Katrin ED - Wilk, Nicole M. ID - 46561 KW - Kommunikationsgeschichte SN - 9783847116127 T2 - Kommunikative Praktiken im Nationalsozialismus TI - »Das dankst du deinem Führer« – Adressierungspraktiken in der Widerstandskommunikation gegen den Nationalsozialismus VL - 3 ER - TY - CHAP AU - Biehler, Rolf AU - Frischemeier, Daniel AU - Gould, Ronald AU - Pfannkuch, Maxine ED - Pepin, Birgit ED - Gueudet, Ghislaine ED - Choppin, Jeffrey ID - 48042 T2 - Handbook of Digital Resources in Mathematics Education TI - Impacts of Digitalization on Content and Goals of Statistics Education ER - TY - BOOK ED - Schuster, Britt-Marie ED - Markewitz, Friedrich ED - Wilk, Nicole M. ID - 48043 TI - Widerstandshandeln. Sprachliche Praktiken des Sich-Widersetzens zwischen 1933 und 1945 VL - 4 ER - TY - JOUR AB - ZusammenfassungDieser Beitrag widmet sich dem Zusammenhang von geistesgeschichtlicher Literaturgeschichtsschreibung und dem Konzept der ›deutschen Bewegung‹. Er rekonstruiert vor allem dessen germanistische Adaption und Weiterentwicklung durch Paul Kluckhohn sowie seinen polyvalenten Einsatz zum heft- und jahrgangsübergreifenden Erzählen einer fortgesetzten nationalen Geistesgeschichte in der Deutschen Vierteljahrsschrift. AU - Gretz, Daniela ID - 48047 IS - 3 JF - Deutsche Vierteljahrsschrift für Literaturwissenschaft und Geistesgeschichte KW - Literature and Literary Theory KW - Philosophy KW - Cultural Studies SN - 0012-0936 TI - »Viele alte Aufgaben wurden damit in einem neuen Lichte gesehen« VL - 97 ER - TY - JOUR AU - Humpert, Lynn AU - Wäschle, Moritz AU - Horstmeyer, Sarah AU - Anacker, Harald AU - Dumitrescu, Roman AU - Albers, Albert ID - 48051 JF - Procedia CIRP KW - General Medicine SN - 2212-8271 TI - Stakeholder-oriented Elaboration of Artificial Intelligence use cases using the example of Special-Purpose engineering VL - 119 ER -