%0 Journal Article %1 PhysRevB.100.035444 %A Wehmeier, Lukas %A Lang, Denny %A Liu, Yongmin %A Zhang, Xiang %A Winnerl, Stephan %A Eng, Lukas M. %A Kehr, Susanne C. %D 2019 %I American Physical Society %J Phys. Rev. B %K c %N 3 %P 035444 %R 10.1103/PhysRevB.100.035444 %T Polarization-dependent near-field phonon nanoscopy of oxides: SrTiO$_3$, LiNbO$_3$, and PbZr$_0.2$Ti$_0.8$O$_3$ %U https://link.aps.org/doi/10.1103/PhysRevB.100.035444 %V 100 %X Resonant infrared near-field optical spectroscopy provides a highly material-specific response with subwavelength lateral resolution of ∼10nm. Here, we report on the study of the near-field response of selected paraelectric and ferroelectric materials, i.e., $SrTiO_3$, $LiNbO_3$, and $PbZr_0.2Ti_0.8O_3$, showing resonances in the wavelength range from 13.0 to 15.8μm. We investigate these materials using scattering scanning near-field optical microscopy in combination with a tunable mid-infrared free-electron laser. Fundamentally, we demonstrate that phonon-induced resonant near-field excitation is possible for both p- and s-polarized incident light, a fact that is of particular interest for the nanoscopic investigation of anisotropic and hyperbolic materials. Moreover, we exploit that near-field spectroscopy, as compared to far-field techniques, bears substantial advantages such as lower penetration depths, stronger confinement, and a high spatial resolution. The latter permits the investigation of minute material volumes, e.g., with nanoscale changes in crystallographic structure, which we prove here via near-field imaging of ferroelectric domain structures in $PbZr_0.2Ti_0.8O_3$ thin films.

@article{PhysRevB.100.035444, abstract = {Resonant infrared near-field optical spectroscopy provides a highly material-specific response with subwavelength lateral resolution of ∼10nm. Here, we report on the study of the near-field response of selected paraelectric and ferroelectric materials, i.e., $SrTiO_3$, $LiNbO_3$, and $PbZr_{0.2}Ti_{0.8}O_3$, showing resonances in the wavelength range from 13.0 to 15.8μm. We investigate these materials using scattering scanning near-field optical microscopy in combination with a tunable mid-infrared free-electron laser. Fundamentally, we demonstrate that phonon-induced resonant near-field excitation is possible for both p- and s-polarized incident light, a fact that is of particular interest for the nanoscopic investigation of anisotropic and hyperbolic materials. Moreover, we exploit that near-field spectroscopy, as compared to far-field techniques, bears substantial advantages such as lower penetration depths, stronger confinement, and a high spatial resolution. The latter permits the investigation of minute material volumes, e.g., with nanoscale changes in crystallographic structure, which we prove here via near-field imaging of ferroelectric domain structures in $PbZr_{0.2}Ti_{0.8}O_3$ thin films.}, added-at = {2019-08-14T10:53:13.000+0200}, author = {Wehmeier, Lukas and Lang, Denny and Liu, Yongmin and Zhang, Xiang and Winnerl, Stephan and Eng, Lukas M. and Kehr, Susanne C.}, biburl = {https://www.bibsonomy.org/bibtex/23840656b3913002aaf280a4eba14fd59/ctqmat}, day = 29, description = {Phys. Rev. B 100, 035444 (2019) - Polarization-dependent near-field phonon nanoscopy of oxides: ${\mathrm{SrTiO}}_{3}, {\mathrm{LiNbO}}_{3}$, and ${\mathrm{PbZr}}_{0.2}{\mathrm{Ti}}_{0.8}{\mathrm{O}}_{3}$}, doi = {10.1103/PhysRevB.100.035444}, interhash = {8daed41f98a8205b610f3f5e88917609}, intrahash = {3840656b3913002aaf280a4eba14fd59}, journal = {Phys. Rev. B}, keywords = {c}, month = {07}, number = 3, numpages = {13}, pages = 035444, publisher = {American Physical Society}, timestamp = {2023-10-18T12:49:48.000+0200}, title = {Polarization-dependent near-field phonon nanoscopy of oxides: SrTiO$_{\mathbf{3}}$, LiNbO$_{\mathbf{3}}$, and PbZr$_{\mathbf{0.2}}$Ti$_{\mathbf{0.8}}$O$_{\mathbf{3}}$}, url = {https://link.aps.org/doi/10.1103/PhysRevB.100.035444}, volume = 100, year = 2019 }