Strongly Correlated Systems KTH


Consequences of a non-trivial band-structure - AVHANDLINGAR.SE

Angle Resolved Photoemission Spectroscopy (ARPES) and Time-Resolved ARPES Fragility of the Dirac Cone Splitting in Topological Crystalline Insulator  several experimental quantities like e.g. ARPES and tunneling spectra. interest include topological materials like topological insulators and  Tunable band gap in 1T' WSe2 with Rb doping. a ARPES maps taken at Two-dimensional (2D) topological insulators (TIs) are promising platforms for  12-ARPES Ultra High Resolution Photoemission station. One-Cubed ARPES.

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It has already been used to show the highest ever observed spin polarization from these topological surface states as well as the persistence of these spin polarizations at room temperature. ARPES study of the epitaxially grown topological crystalline insulator SnTe(111) From the doping evolution of the FS topology and the band dispersions shown above, we have found convincing evidence that the 0.67% Sn-doped Bi 2 Te 3 is a 3D topological insulator with a single Techniques such as angle-resolved photoemission spectrometry (ARPES), advanced solid-state Nuclear Magnetic Resonance (NMR) or scanning-tunnel microscopy (STM) together with key principles of topological insulators such as spin-locked electronic states, the Dirac point, quantum Hall effects and Majorana fermions are illuminated in individual chapters and are described in a clear and logical form. Key words: circular dichroism, ARPES, spin texture, topological insulator, spin-orbit coupling Corresponding author: e-mail, Phone: +617-253-3420, Fax: +617-258-6883 Topological insulators are a new phase of matter that ex-hibits exotic surface electronic properties. Determining the spin texture of this class of material is of paramount A topological insulator is a material that behaves as an insulator in its interior but whose surface contains conducting states, meaning that electrons can only move along the surface of the material. Topological insulators have non-trivial symmetry-protected topological order; however, having a conducting surface is not unique to topological insulators, since ordinary band insulators can also support conductive surface states.

High quality samples with relatively small band gaps and a low energy Dirac point were used.

Strong and Weak Topology Probed by Surface Science

Ongoing research is hampered by the scarcity of model material families, consisting of only the 4f rare-earth boride compounds thus far. Here we establish a class of candidate topological Kondo insulator in FeSb2, based on Here, we present detailed observations of two magnetic topological insulators, one newly predicted, that provide new insight into how to control their novel behavior.

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From a different perspective, carefully doped topological insulators can provide a platform to study the interplay between TSS and bulk electron dynamics, which has im-portant implications for TSS control and exploring topo-logical superconductivity [18].

Arpes topological insulator

a) ARPES data for Bi2Se3 reveal surface  21 Aug 2015 Topological insulators (TIs) are a new quantum state of matter. Angle resolved photoemission spectroscopy (ARPES) implemented by a  15 Dec 2011 Three-dimensional topological insulators (TIs), discovered experimentally in 2007–2009 by a Princeton–ALS collaboration, are a promising  11 Aug 2015 surface of the prototypical topological insulator (TI) Bi2Se3. For the rational angle resolved photoemission spectroscopy (ARPES) studies,. 5 May 2009 materials drive development of experimental technology. • Cuprates. • Iron-based superconductors.
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We conclude  Topological insulators represent a new quantum state of matter which are The spin polarization of electrons can be determined by the spin-resolved ARPES  resolved photoelectron spectroscopy (ARPES). Since the discovery of topological insulators (TIs) and. Fe- based high-temperature superconductors (FeSCs),. dc.description.abstract, Topological Insulators (TIs) have become one of the level measured by Angle- Resolved Photoemission Spectroscopy (ARPES),  13 Jul 2020 Discovery of 2D topological insulator (TI) in HgTe/CdTe and 3D TI in studied by angle-resolved photoemission spectroscopy (ARPES). Angle-resolved photoemission (ARPES) played a leading role in the discovery of three-dimensional topological insulators, and in particular their characteristic  A topological insulator (TI) has conducting surface states (SSs) protected by the non- Combined with angle-resolved photoemission spectroscopy (ARPES)  16 Mar 2020 Topological insulators (TIs) are bulk insulating materials that nonetheless Comparison between the experimental ARPES data and the  ARPES Angle-resolved photoemission spectroscopy.

have now shown that adding copper to a particular topological insulator makes it superconducting—a "topological superconductor" that could transform the way information is stored and processed, in low-power-consumption devices that are not only '"green," but also immune to the overheating problems that befall current silicon-based electronics. While the ARPES and STM measurements usually involve the fresh surface obtained by cleaving samples in situ under ultrahigh vacuum, for the transport and optical techniques, which are widely used to investigate the intrinsic quantum behaviors of the topological surface state (36 ⇓ ⇓ ⇓ –40), and particularly the ultimate applications of the topological insulators, the surface is usually Topological Insulators I. INTRODUCTION Topological quantum materials (TQMs) represent spe-cial classes of materials whose electronic structures can be characterized by topological invariants protected by certain symmetries, and the breaking of these symmetries can lead to intriguing topological phase transitions. Time- Topological Insulator Material “insulator” by definition: Bulk insulating Surface metallic (2D) (real space) bulk High quality: low defect/impurity density If the bulk is conducting, it is difficult to measure the transport property of its surface with exotic topological property.
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Spin-polarized 001 surface states of the topological crystalline

the first topological insulator to be discovered, Bi xSb 1 x (7). The 2D topological invariant underlies the spin QHE observed in quantum wells derived from HgTe (8, 9). The general term topological insulators was coined to indicate that both the 2D and 3D phases are topological in 2012-05-14 · ARPES maps the electronic properties, including the band structure and Fermi surface, of the topological insulator bismuth selenide (left).

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Experimental Facilities at BESSY II and BER II - Helmholtz

We observe both bulk and surface bands in the electronic spectra, in ARPES in topological insulator mistakes electron's momentum for massless Dirac fermion. Topological Insulators in 2D and 3D I. Introduction - Graphene - Time reversal symmetry and Kramers‟ theorem II. 2D quantum spin Hall insulator - Z 2 topological invariant - Edge states - HgCdTe quantum wells, expts III. Topological Insulators in 3D - Weak vs strong - Topological invariants from band structure IV. The surface of a topological It focuses on experimental efforts in discovering new topological states and new topological phenomena beyond the 3D TI state including topological Kondo insulator (TKI), topological quantum phase transition, topological Dirac semimetals (TDS), magnetic and superconductor TIs, and topological crystalline insulators (TCI), respectively.