Weak-antilocalization and surface dominated transport in topological insulator Bi2Se2Te

Gopal, Radha Krishna; Singh, Sourabh; Chandra, Ramesh; Mitra, Chiranjib

doi:10.1063/1.4917455

Cited by 44 publications

(33 citation statements)

References 47 publications

(132 reference statements)

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“…With increasing temperature, the region of linearity is suppressed, as well as the magnitude of the sudden upturn in MR. This sudden upturn in MR has been observed in other systems and can be explained by quantum interference effects such as weak localization or weak antilocalization, the latter of which has often been observed in the 2D Dirac surface states of topological insulators and in 3D Dirac semimetal thin films [34][35][36][37] . Furthermore, linear magnetoresistance has been known to arise in topological systems, and its presence in LaCuSb2 further gives evidence for the presence of Dirac fermions in this system.…”

Section: Resultsmentioning

confidence: 72%

Dirac fermions and possible weak antilocalization in LaCuSb2

et al. 2019

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Layered heavy-metal square-lattice compounds have recently emerged as potential Dirac fermion materials due to bonding within those sublattices. We report quantum transport and spectroscopic data on the layered Sb square-lattice material LaCuSb2. Linearly dispersing band crossings, necessary to generate Dirac fermions, are experimentally observed in the electronic band structure observed using angle-resolved photoemission spectroscopy (ARPES), along with a quasi-two-dimensional Fermi surface. Weak antilocalization that arises from two-dimensional transport is observed in the magnetoresistance, as well as regions of linear dependence, both of which are indicative of topologically non-trivial effects. Measurements of the Shubnikovde Haas (SdH) quantum oscillations show low effective mass electrons on the order of 0.065me, further confirming the presence of Dirac fermions in this material.

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Section: Resultsmentioning

confidence: 72%

Dirac fermions and possible weak antilocalization in LaCuSb2

et al. 2019

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“…Phase coherence length decreases with temperature with a power law variation ~T −p , where p depends on the dimensionality of the system and the agents responsible for the dephasing mechanism 42, 43 . For the three films under study in our case i.e., B1, B2 and B3 the value of p = 0.61, 0.31and 0.64 respectively 35 . Detailed investigation of this coefficient ‘p’ is being carried out for a variety of films.…”

Section: Resultsmentioning

confidence: 94%

Topological delocalization and tuning of surface channel separation in Bi2Se2Te Topological Insulator Thin films

Gopal

Singh

Mandal

et al. 2017

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The surface states of a 3D topological insulator (TI) exhibit topological protection against backscattering. However, the contribution of bulk electrons to the transport data is an impediment to the topological protection of surface states. We report the tuning of the chemical potential in the bulk in Bi2Se2Te TI thin films, pinning it near the center of the bulk band gap, thereby suppressing the bulk carriers. The temperature dependent resistance of these films show activated behavior down to 50 K, followed by a metallic transition at lower temperatures, a hallmark of robustness of TI surface states. Manifestation of topological protection and surface dominated transport is explained by 2D weak antilocalization phenomenon. We further explore the effect of surface to bulk coupling in TI in this work, which is captured by the number of effective conducting surface channels that participate in the transport. The presence of a single conducting channel indicates a strong surface to bulk coupling which is detrimental to purely topological transport. We demonstrate the decoupling of topological surface states on opposite surfaces of thin films, thereby suppressing the bulk transport. Our findings provide a deeper understanding of surface to bulk coupling along with topological transport behavior and their respective tunability.

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“…Considering that the bulk state without the WAL effect has no contribution to α value, the extracted value of 0.60 larger than 0.5 may be mainly due to partial interaction between the top and the bottom surface states. In topological insulator Bi 2 Se 2 Te films and Sb 2 Te 3 films, the α value shows an increase with increasing T , which is explained respectively by thermally excited bulk carriers and transport disorder . Due to T independence of electron density from 2 K up to 8 K (not shown here), thermally excited bulk carrier must be negligible in our samples.…”

Section: Resultsmentioning

confidence: 74%

Time‐Dependent Electrical Transport Properties of Topological Insulator Cr‐Doped Bi₂Se₃ Thin Films

Zhang

Wang

et al. 2019

Physica Status Solidi (b)

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This paper reports the research of the electrical transport properties of Cr‐doped Bi2Se3 thin films. The films with a uniform Cr distribution exhibit the same structure as undoped Bi2Se3 thin film. At low temperatures, both the weak antilocalization (WAL) and the electron–electron interaction (EEI) effects are observed. From the WAL effect, the dephasing length and the number of the transport channels are extracted. The temperature dependence of the extracted dephasing length can be described by both the Nyquist electron–electron and the electron–phonon scatterings. With increasing time in vacuum, the resistances of the thin films exhibit a transition from the negative to the positive temperature coefficient, with an increase in electron density. Unexpectedly, the number of the transport channels extracted from the WAL effect is found to increase with increasing time, which is further confirmed by analyzing the EEI effect. This observation can be attributed to the presence of two‐dimensional electron gas on the surface of films, which is likely to be formed through the surface reaction with water.

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Weak-antilocalization and surface dominated transport in topological insulator Bi2Se2Te

Cited by 44 publications

References 47 publications

Dirac fermions and possible weak antilocalization in LaCuSb2

Dirac fermions and possible weak antilocalization in LaCuSb2

Topological delocalization and tuning of surface channel separation in Bi2Se2Te Topological Insulator Thin films

Time‐Dependent Electrical Transport Properties of Topological Insulator Cr‐Doped Bi₂Se₃ Thin Films

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Weak-antilocalization and surface dominated transport in topological insulator Bi2Se2Te

Cited by 44 publications

References 47 publications

Dirac fermions and possible weak antilocalization in LaCuSb2

Dirac fermions and possible weak antilocalization in LaCuSb2

Topological delocalization and tuning of surface channel separation in Bi2Se2Te Topological Insulator Thin films

Time‐Dependent Electrical Transport Properties of Topological Insulator Cr‐Doped Bi2Se3 Thin Films

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Time‐Dependent Electrical Transport Properties of Topological Insulator Cr‐Doped Bi₂Se₃ Thin Films