Modulation-Doping a Correlated Electron Insulator

Debasish Mondal; Smruti Rekha Mahapatra; Abigail M Derrico; Rajeev Kumar Rai; Jay R Paudel; Christoph Schlueter; Andrei Gloskovskii; Rajdeep Banerjee; Frank M F DeGroot; Dipankar D Sarma; Awadhesh Narayan; Pavan Nukala; Alexander X Gray; Naga Phani B Aetukuri

arXiv · 2301.02798

Modulation-Doping a Correlated Electron Insulator

Debasish Mondal·Smruti Rekha Mahapatra·Abigail M Derrico·Rajeev Kumar Rai·Jay R Paudel·Christoph Schlueter·Andrei Gloskovskii·Rajdeep Banerjee·Frank M F DeGroot·Dipankar D Sarma·Awadhesh Narayan·Pavan Nukala·Alexander X Gray·Naga Phani B Aetukuri

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Abstract

Correlated electron materials (CEMs) host a rich variety of condensed matter phases. Vanadium dioxide (VO2) is a prototypical CEM with a temperature-dependent metal-to-insulator (MIT) transition with a concomitant crystal symmetry change. External control of MIT in VO2 - especially without inducing structural changes - has been a long-standing challenge. In this work, we design and synthesize modulation-doped VO2-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 5x10^21 cm^(-3) without inducing any measurable structural changes. We find that the MIT temperature (T_MIT) continuously decreases with increasing carrier concentration. Remarkably, the insulating state is robust even at doping concentrations as high as ~0.2 e-/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.

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Debasish Mondal, Smruti Rekha Mahapatra, Abigail M Derrico, Rajeev Kumar Rai, Jay R Paudel, Christoph Schlueter, Andrei Gloskovskii, Rajdeep Banerjee, Frank M F DeGroot, Dipankar D Sarma, Awadhesh Narayan, Pavan Nukala, Alexander X Gray, Naga Phani B Aetukuri. 2023-01-07. Modulation-Doping a Correlated Electron Insulator. https://arxiv.org/abs/2301.02798

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