Enhancing High-Frequency Properties of Nanocrystalline Sputtered Fe Thin Films by Using MnIr Underlayer and Oblique Deposition

We study the surface crystalline and electronic structures of the antiferromagnetic topological insulator MnBi2Te4 using scanning tunneling microscopy/spectroscopy (STM/S), micro(μ)-laser angle-resolved photoemission spectroscopy (ARPES), and density functional theory calculations. Our STM images reveal native point defects at the surface that we identify as BiTe antisites and MnBi substitutions. Bulk X-ray diffraction further evidences the presence of the Mn-Bi intermixing. Overall, our characterizations suggest that the defects concentration is nonuniform within crystals and differs from sample to sample. Consistently, the ARPES and STS experiments reveal that the Dirac point gap of the topological surface state is different for different samples and sample cleavages, respectively. Our calculations show that the antiparallel alignment of the MnBi moments with respect to those of the Mn layer can indeed cause a strong reduction of the Dirac point gap size. The present study provides important insights into a highly debated issue of the MnBi2Te4 Dirac point gap.

show abstract

Native point defects and their implications for the Dirac point gap at MnBi2Te4(0001)

Garnica

Otrokov

Aguilar

et al. 2022

npj Quantum Mater.

View full text Add to dashboard Cite

show abstract

Existence of electron–hole charge puddles and the observation of strong universal conductance fluctuations in a 3D topological insulator

Mallick

Mandal

Ganesan

et al. 2021

Applied Physics Letters

View full text Add to dashboard Cite

Phase-coherent transport manifests itself in various quantum phenomena. Universal conductance fluctuations (UCF) are one of them. Here, we report the detailed study of dephasing of electronic wavefunction by analyzing UCF and weak antilocalization in a device, made by exfoliation from a bulk insulating topological insulator single crystal (Bi1Sb1Te1.5Se1.5). From the parallel magnetic field measurement, we proved that the quantum phenomena in our sample are caused by surface Dirac electrons. Our sample showed very slow dephasing of electronic wavefunction, which has rarely been observed in topological insulator materials. This kind of dephasing indicates the presence of electron–hole charge puddles in our system. The RMS amplitude of the UCF is also surprisingly higher (13 e2h) than the universal value of the conductance fluctuation (e2h) and the fluctuations persist in our sample until the temperature as high as 20 K and above. We also show that the shape of the flake has a significant impact on the prefactor, α, of the Hikami–Larkin–Nagaoka equation. Moreover, the formation of Aharonov–Bohm loops of different areas is responsible for UCF. By analyzing the fast Fourier transform of the UCF data, we have obtained these Aharonov–Bohm loops which are contributing to the UCF.

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Enhancing High-Frequency Properties of Nanocrystalline Sputtered Fe Thin Films by Using MnIr Underlayer and Oblique Deposition

Cited by 2 publications

References 24 publications

Native point defects and their implications for the Dirac point gap at MnBi2Te4(0001)

Native point defects and their implications for the Dirac point gap at MnBi2Te4(0001)

Existence of electron–hole charge puddles and the observation of strong universal conductance fluctuations in a 3D topological insulator

Contact Info

Product

Resources

About