visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
날짜 2023-10-19 11:00 
일시 Oct.19(Thu). 11:00AM 
장소 E6-2 #1322 
연사 Dr. Ji Soo Lim (Universität Würzburg, Germany) 
10월 19일 목요일  개최 예정인 세미나 관련하여, 아래와 같이 안내 드립니다.
관심있는 분들의 많은 참여 바랍니다.
 
- Speaker : Dr. Ji Soo Lim (Physikalisches Institut and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Germany)
- Time : 2023.10.19(Thu). 11:00 ~ 
- Place : E6-2  #1322
- Title : "Emergent functionalities of iridium oxide films with different growth orientation"
- Abstract : 
Iridium-based 5d transition metal oxides have been focused on realizing novel superconductivity or topological phases with an interplay between large spin-orbit coupling (0.3~0.4 eV) and short-range electron-electron interaction (~0.5 eV) [1, 2, 3]. The strontium iridate Ruddlesden-Popper compounds Srn+1IrnO3n+1 = ([SrIrO3]n, SrO) essentially consist of n SrIrO3 perovskite layers, intercalated by SrO layers and laterally shifted against each other such that no Ir-O-Ir bonds persist between neighbouring [SrIrO3]n blocks. As one veers away from the quasi-2D limit (Sr2IrO4, n=1) the Mott-insulating state breaks down as evidenced by the narrow-gap bilayer system Sr3Ir2O7 (n=2) hosting a collinear antiferromagnetic order and the metastable three-dimensional semi metallic and paramagnetic SrIrO3 (n=∞) [2, 4]. Additionally, SrIrO3 (001) films have been shown a highly active and stable catalyst by Sr leaching from the surface [5].
 
In this presentation, I present our findings on the epitaxial growth of SrIrO3 films with varying thickness on SrTiO3 (001) and (111) substrates. For the SrIrO3 (001) film, a critical thickness of 4 unit cells marks a dimensionality-controlled metal-insulator transition (MIT). This transition coincides with the emergence of octahedral rotation [6]. Below this threshold, we anticipate the presence of canted antiferromagnetism, where the net magnetic moment aligns in the in-plane direction. Additionally, the monolayer SrIrO3 (001) film exhibits a band structure akin to that of Sr2IrO4, a material often considered as a parent substance for unconventional superconductivity.
 
In case of SrIrO3 (111) film, it manifests a twinned superstructure with a periodicity of 3 unit cells for films thicker than 4 unit cells. Transmission electron microscopy (TEM) reveals that the interfaces between the 3-unit cell thick stacks consist of face-sharing octahedra with a larger Ir-Ir lattice spacing compared to within the stacks. This twinned superstructure aligns with the observed MIT at a critical thickness of 5 unit cells. In the SrIrO3 (111) films exceeding 5 unit cells, we observe a sign change of the magnetoresistance from positive to negative and the emergence of hysteresis loops in the anomalous Hall effect at about 10 K. These findings provide strong evidence for the existence of ferromagnetic phases.
 
Combined with theoretical and experimental results in our films, I explain electronic carrier properties of both SrIrO3 (001) and (111) films, corroborated by band structure calculation. Also, I discuss the microscopic origin of AHEs in relation to topological effects, paving the way for discovering the topological phases.
 
 
번호 날짜 장소 제목
237 2022-11-03 16:00  E6-2 #1323  (광학분야 세미나) Single-photon emission from low-dimensional materials
236 2023-06-01 16:00  E6-2 #1323  (광학분야 세미나)Quantum sensing using a squeezed light from hot Rb vapor
235 2022-10-28 11:00  E6-2 #1323  [Update 세미나영상] (응집물리 세미나) Machine-Learning-Guided Prediction models and Materials discovery for high Tc cuprates file
234 2022-12-09 11:00  E6-2 #1323  [Update 세미나영상](응집물리 세미나) Single-shot measurements of strongly-correlated artificial molecular levels in semiconductor quantum dots file
233 2023-03-16 16:00  E6-2 #1323  2023 봄학기 광학분야 및 응집물리 특별세미나 전체 일정 file
232 2022-11-25 11:00  E6-2 #1323  [Update 세미나영상](응집물리 세미나) DMFT+ NRG: From models to real materials, from local to nonlocal correlations file
231 2017-10-10 16:00  E6-2 #1323  Discovery of New 2D Materials with Diverse Physical Properties
230 2020-10-23 14:00  E6-2 #1323  Plasmon spectroscopy of low-dimensional superconductors in fluctuating regime file
229 2023-04-27 11:00  E6-2 #1322  Inverse Shapiro steps and coherent quantum phase slip in superconducting nanowires
228 2022-12-13 11:00  E6-2 #1322  Art of thin film engineering toward topological quantum computation file
227 2024-01-26 15:00  E6-2 #1323  In-situ 4D-STEM studies on surface reconstruction and polarization switching of perovskite oxides
» 2023-10-19 11:00  E6-2 #1322  Emergent functionalities of iridium oxide films with different growth orientation file
225 2018-12-26 16:00  E6-1. 3rd fl. #3434  Informal Workshop on Topology and Correlation file
224 2018-10-24 10:30  E6-1, Lecture Room 1501(1F)  Photonic integration of next-generation clocks and Hertz-absolute-accuarcy optical frequenncy synthesizers file
223 2024-02-26 16:00  E6-1 #1501  2024 봄학기 콜리키움 전체 일정 newfile
222 2023-08-24 12:00  E6-1 #1501  2023 가을학기 콜로키움 전체 일정 file
221 2022-09-21 10:30  E6-1 #1501  [Update 세미나 영상] Distinguished Lecture 'The Magic of Moiré Quantum Matter' Prof. Pablo Jarillo-Herrero(Department of Physics, MIT) file
220 2023-02-27 12:00  E6-1 #1501  2023 봄학기 콜로키움 전체 일정 file
219 2022-04-08 11:00  E6-1 #1323  (응집물리 세미나) Flat-surface-assisted physical phenomena occurring in single crystal metal thin film file
218 2022-08-12 10:00  E6-1 #1323  Twisted Bilayer Magnets file