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Title: Amperean Pairing at the Surface of Topological Insulators

Authors:
; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1294687
Grant/Contract Number:
DESC0001911
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 117; Journal Issue: 7; Related Information: CHORUS Timestamp: 2016-08-12 18:10:24; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English

Citation Formats

Kargarian, Mehdi, Efimkin, Dmitry K., and Galitski, Victor. Amperean Pairing at the Surface of Topological Insulators. United States: N. p., 2016. Web. doi:10.1103/PhysRevLett.117.076806.
Kargarian, Mehdi, Efimkin, Dmitry K., & Galitski, Victor. Amperean Pairing at the Surface of Topological Insulators. United States. doi:10.1103/PhysRevLett.117.076806.
Kargarian, Mehdi, Efimkin, Dmitry K., and Galitski, Victor. 2016. "Amperean Pairing at the Surface of Topological Insulators". United States. doi:10.1103/PhysRevLett.117.076806.
@article{osti_1294687,
title = {Amperean Pairing at the Surface of Topological Insulators},
author = {Kargarian, Mehdi and Efimkin, Dmitry K. and Galitski, Victor},
abstractNote = {},
doi = {10.1103/PhysRevLett.117.076806},
journal = {Physical Review Letters},
number = 7,
volume = 117,
place = {United States},
year = 2016,
month = 8
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevLett.117.076806

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  • Here, we show that the chemical inhomogeneity in ternary three-dimensional topological insulators preserves the topological spin texture of their surface states against a net surface magnetization. The spin texture is that of a Dirac cone with helical spin structure in the reciprocal space, which gives rise to spin-polarized and dissipation-less charge currents. Thanks to the nontrivial topology of the bulk electronic structure, this spin texture is robust against most types of surface defects. However, magnetic perturbations break the time-reversal symmetry, enabling magnetic scattering and loss of spin coherence of the charge carriers. This intrinsic incompatibility precludes the design of magnetoelectronicmore » devices based on the coupling between magnetic materials and topological surface states. We demonstrate that the magnetization coming from individual Co atoms deposited on the surface can disrupt the spin coherence of the carriers in the archetypal topological insulator Bi 2Te 3, while in Bi 2Se 2Te the spin texture remains unperturbed. This is concluded from the observation of elastic backscattering events in quasiparticle interference patterns obtained by scanning tunneling spectroscopy. The mechanism responsible for the protection is investigated by energy resolved spectroscopy and ab initio calculations, and it is ascribed to the distorted adsorption geometry of localized magnetic moments due to Se–Te disorder, which suppresses the Co hybridization with the surface states.« less
  • Topological insulators are new states of quantum matter in which surface states residing in the bulk insulating gap of such systems are protected by time-reversal symmetry. The study of such states was originally inspired by the robustness to scattering of conducting edge states in quantum Hall systems. Recently, such analogies have resulted in the discovery of topologically protected states in two-dimensional and three-dimensional band insulators with large spin-orbit coupling. So far, the only known three-dimensional topological insulator is Bi{sub x}Sb{sub 1-x}, which is an alloy with complex surface states. Here, we present the results of first-principles electronic structure calculations ofmore » the layered, stoichiometric crystals Sb{sub 2}Te{sub 3}, Sb{sub 2}Se{sub 3}, Bi{sub 2}Te{sub 3} and Bi{sub 2}Se{sub 3}. Our calculations predict that Sb{sub 2}Te{sub 3}, Bi{sub 2}Te{sub 3} and Bi{sub 2}Se{sub 3} are topological insulators, whereas Sb{sub 2}Se{sub 3} is not. These topological insulators have robust and simple surface states consisting of a single Dirac cone at the point. In addition, we predict that Bi{sub 2}Se{sub 3} has a topologically non-trivial energy gap of 0.3 eV, which is larger than the energy scale of room temperature. We further present a simple and unified continuum model that captures the salient topological features of this class of materials.« less