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Facet‐Dependent Phase Control by Band Filling and Anisotropic Electron–Lattice Coupling in HVO 2 Epitaxial Films
Author(s) -
Yoon Hyojin,
Park Jaeseoung,
Choi SiYoung,
Lee Donghwa,
Son Junwoo
Publication year - 2018
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.201800128
Subject(s) - materials science , facet (psychology) , anisotropy , condensed matter physics , lattice (music) , epitaxy , electronic structure , phase transition , doping , dopant , interstitial defect , crystal structure , crystallography , nanotechnology , optoelectronics , optics , chemistry , physics , psychology , social psychology , personality , acoustics , big five personality traits , layer (electronics)
Unlike the substitutional dopants, interstitial hydrogen effectively supplies significant amount of carriers in the empty narrow d band in correlated electronic systems by reversibly adding it into interstitial sites. Here, it is demonstrated that hydrogenated VO 2 , a heavily hydrogenated correlated insulating phase with 3d 2 electronic configuration, can be thermodynamically stabilized by topotactically preserving its lattice framework regardless of the facet direction of VO 2 epilayers. However, the kinetics of phase modulation and the response of out‐of‐plane lattice expansion are clearly affected by the orientation of the crystal facet, which is attributed to the anisotropy in the diffusion of hydrogen atoms and to anisotropic expansion induced by chemical stress. This result demonstrates universal electron‐doping‐induced phase transition near‐integer numbers of d band filling in correlated electronic systems and also supports the idea that orientation of crystallographic facets can be exploited to control the rate of electronic phase transition and the degree of electron–lattice coupling.