Dresden 2017 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
DS: Fachverband Dünne Schichten
DS 36: Postersession I
DS 36.17: Poster
Mittwoch, 22. März 2017, 17:00–19:00, P2-EG
Direct observation of the M2 phase with its Mott transition in a VO2 film — Hoon Kim1,2, Tetiana Slusar3, •Dirk Wulferding1,4, Ilkyu Yang1, Jin-Cheol Cho3, Minkyung Lee1,5, Hee Cheul Choi1,5, Yoon Hee Jeong2, Hyun-Tak Kim3, and Jeehoon Kim1,2 — 1CALDES, Institute for Basic Science, Pohang, Korea — 2Dept. of Phys., POSTECH, Pohang, Korea — 3ETRI, Daejeon, Korea — 4IPKM und LENA, TU-BS, Braunschweig, Germany — 5Dept. of Chem., POSTECH, Pohang, Korea
In VO2, the explicit origin of the insulator-to-metal transition is still disputable between Peierls and Mott insulators. Along with the controversy, its second monoclinic (M2) phase has received considerable attention due to the presence of electron correlation in undimerized vanadium ions. However, the origin of the M2 phase is still obscure. We study a granular VO2 film using conductive atomic force microscopy and Raman scattering. Upon the structural transition from monoclinic to rutile, we observe directly an intermediate state showing the coexistence of monoclinic M1 and M2 phases. The conductivity near the grain boundary in this regime is six times larger than that of the grain core, producing a donut-like landscape. Our results reveal an intra-grain percolation process, indicating that VO2 with the M2 phase is a Mott insulator. [H. Kim, et al., arXiv:1611.09508 (2016).]