Modulation-doping a correlated electron insulator.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37798279.
- Also identified by DOI 10.1038/s41467-023-41816-3 and PMC identifier 10556139.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Correlated electron materials (CEMs) host a rich variety of condensed matter phases. Vanadium dioxide (VO<sub>2</sub>) is a prototypical CEM with a temperature-dependent metal-to-insulator (MIT) transition with a concomitant crystal symmetry change. External control of MIT in VO<sub>2</sub>-especially without inducing structural changes-has been a long-standing challenge. In this work, we design and synthesize modulation-doped VO<sub>2</sub>-based thin film heterostructures that closely emulate a textbook example of filling control in a correlated electron insulator. Using a combination of charge transport, hard X-ray photoelectron spectroscopy, and structural characterization, we show that the insulating state can be doped to achieve carrier densities greater than 5 × 10<sup>21</sup> cm<sup>-3</sup> without inducing any measurable structural changes. We find that the MIT temperature (T<sub>MIT</sub>) continuously decreases with increasing carrier concentration. Remarkably, the insulating state is robust even at doping concentrations as high as ~0.2 e<sup>-</sup>/vanadium. Finally, our work reveals modulation-doping as a viable method for electronic control of phase transitions in correlated electron oxides with the potential for use in future devices based on electric-field controlled phase transitions.