Abstract
The 2‐dimensional electron gas (2DEG) found at the surface of SrTiO3 and related interfaces has attracted significant attention as a promising basis for oxide electronics. In order to utilize its full potential, the response of this 2DEG to structural changes and surface modification must be understood in detail. Here, a study of the detailed electronic structure evolution of the 2DEG as a function of sample temperature and surface step density is presented. By comparing the experimental results with ab initio calculations, it is shown that local structure relaxations cause a metal‐insulator transition of the system around 135 K. This study presents a new and simple way of tuning the 2DEG via surface vicinality and identifies how the operation of prospective devices will respond to changes in temperature.
Highlights
The interest in STO and STO-based heterostructures boosted in the last years related interfaces has attracted significant attention as a promising basis for due to the plethora of intriguing propoxide electronics
In this work we used 0.05 wt% Nb-doped STO samples to ensure that the sample is grounded through its bulk, this way avoiding the need to create a conductive path with light
Our density functional theory (DFT) calculations show that the relaxed structure of a SrOterminated STO (001) surface results in a band structure with correct orbital character and layer origin, as well as a closely matching Δt2g, when compared to the angle-resolved photoemission (ARPES) data
Summary
At the first exposure of the sample to photons of 85 eV, we do not observe any intensity at the Fermi level (EF). It is worth noting, that a recent work employing non-contact atomic force microscopy pointed out that surface reconstructions on STO sometimes cannot be detected by techniques such as photoemission or LEED.[45]. Band dispersion maps were acquired continuously during the ramps, allowing us to track the position of the bands and of the Fermi level EF with temperature. After reaching 125 K, the sample was cooled down to 100 K and heated again to 145 K (ramp 2, Figure 2b) This time the “jump” of EF happened at around 112 K, a slightly higher value than observed during ramp 1. The temperature of the jump is close to the bulk tetragonalcubic phase transition in STO (105 K), and can be explained by the measured electrical transport behavior of Nb:STO crystals, which in the 85–110 K range show a variation while going
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
