2014/01/31 by Martin Setvin, Martin Setvín, Cesare Franchini +8 · 477 citations
Chemistry · Energy · Materials Science · Physics and Astronomy · #Advanced Photocatalysis Techniques #Anatase #Catalytic Processes in Materials Science #Chemistry #Condensed matter physics #Crystallography #Density functional theory #Dopant #Doping #Electron #Lattice (music) #Materials science #Physics #Polaron #Quantum mechanics #Rutile #TiO2 Photocatalysis and Solar Cells #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.113.086402
published in Physical Review Letters 113(8), 086402 (American Physical Society)
arxiv created 2014/07/29 · openalex publication_date 2014/08/18 · arxiv updated 2014/08/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
A combination of scanning tunneling microscopy and spectroscopy and density functional theory is used to characterize excess electrons in TiO2 rutile and anatase, two prototypical materials with identical chemical composition but different crystal lattices. In rutile, excess electrons can localize at any lattice Ti atom, forming a small polaron, which can easily hop to neighboring sites. In contrast, electrons in anatase prefer a free-carrier state, and can only be trapped near oxygen vacancies or form shallow donor states bound to Nb dopants. The present study conclusively explains the differences between the two polymorphs and indicates that even small structural variations in the crystal lattice can lead to a very different behavior.