Reducing the V2O3(0001) surface through electron bombardment--a quantitative structure determination with I/V-LEED

Area of Science:

• Materials Science
• Surface Science
• Solid-State Chemistry

Background:

• Vanadium sesquioxide (V2O3) exhibits complex electronic and magnetic properties sensitive to surface termination.
• Standard ultra-high vacuum preparation results in a vanadyl-terminated V2O3(0001) surface.
• Electron reduction creates a chemically active and ordered V2O3(0001) surface, necessitating structural elucidation.

Purpose of the Study:

• To perform the first quantitative structure determination of a reduced V2O3(0001) surface.
• To identify and characterize distinct surface phases formed after reduction.
• To compare different reduction methods and their resulting surface structures.

Main Methods:

• Scanning Tunneling Microscopy (STM) for identifying surface phases and imaging atomic arrangements.
• I/V-Low Energy Electron Diffraction (LEED) for determining surface periodicity and composition.
• Simulated STM images for structural model validation.

Main Results:

• Two distinct surface phases of reduced V2O3(0001) were identified by STM: one well-ordered and one less ordered.
• The ordered phase was determined to have a surface termination of a single vanadium atom per surface unit cell, situated on a quasi-hexagonal oxygen layer.
• The surface unit cell of the ordered phase contains three atoms.
• Comparison of reduction methods confirmed a proposed structure with three surface vanadium atoms for V deposition onto a vanadyl-terminated film.

Conclusions:

• The ordered reduced V2O3(0001) surface possesses a unique atomic structure with a single surface vanadium atom, distinct from previously proposed models.
• Electron bombardment and V deposition yield different surface reconstructions, highlighting the importance of the reduction method.
• This detailed structural understanding is fundamental for controlling and utilizing the surface properties of V2O3 in catalysis and electronic devices.