Distinct effects of Cr bulk doping and surface deposition on the chemical environment and electronic structure of the topological insulator Bi 2 Se 3
- Univ. of Connecticut, Storrs, CT (United States)
- Princeton Univ., NJ (United States)
- Brookhaven National Lab. (BNL), Upton, NY (United States)
In this report, it is shown that Cr doped into the bulk and Cr deposited on the surface of Bi2Se3 films produced by molecular beam epitaxy (MBE) have strikingly different effects on both the electronic structure and chemical environment. Angle resolved photoemission spectroscopy (ARPES) shows that Cr doped into the bulk opens a surface state energy gap which can be seen at room temperature; much higher than the measured ferromagnetic transition temperature of ≈ 10 K. On the other hand, similar ARPES measurements show that the surface states remain gapless down to 15 K for films with Cr surface deposition. In addition, core-level photoemission spectroscopy of the Bi 5d, Se 3d, and Cr 3p core levels show distinct differences in the chemical environment for the two methods of Cr introduction. Surface deposition of Cr results in the formation of shoulders on the lower binding energy side for the Bi 5d peaks and two distinct Cr 3p peaks indicative of two Cr sites. These striking differences suggests an interesting possibility that better control of doping at only near surface region may offer a path to quantum anomalous Hall states at higher temperatures than reported in the literature.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0012704; AC02-98CH10886
- OSTI ID:
- 1412746
- Alternate ID(s):
- OSTI ID: 1419525
- Report Number(s):
- BNL-114706-2017-JA; R&D Project: PM015; KC0207010
- Journal Information:
- Applied Surface Science, Vol. 407, Issue C; ISSN 0169-4332
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Topological quantum weak antilocalization limit and anomalous Hall effect in semimagnetic Bi 2−x Cr x Se 3 /Bi 2 Se 3−y Tey heterostructure
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journal | November 2019 |
Gap-like feature observed in the non-magnetic topological insulators
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journal | January 2020 |
Photon energy and polarization-dependent electronic structure of Cr-doped
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journal | February 2020 |
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