Weak antilocalization in Sb2Te3 nano-crystalline topological insulator

Bera, Sumit; Behera, P. Suchismita; Mishra, A. K.; Krishnan, M.; Patidar, Manju Mishra; Venkatesh, R.; Ganesan, V.

doi:10.1016/j.apsusc.2019.143654

Cited by 16 publications

(12 citation statements)

References 32 publications

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“…Furthermore, L Φ is within the same range of size of the crystalline grains obtained from HRTEM. The obtained power law is also similar to previously reported behaviors for Sb 2 Te 3 thin films and similar TIs 28,31,55,56 and it is consistent with predominant electron− electron scattering in 2D weakly disordered systems as it is the case for a possible 2D TI state. Thus, in these sputtered thin films, these results appear to suggest the presence of a 2D TIlike surface state, which would be coupled to the n-type and ptype conduction channels.…”

Section: ■ Results and Discussionsupporting

confidence: 90%

“…This behavior combined with the structural characterization and the transport properties suggest a scenario whereby in these nanocrystalline Sb 2 Te 3 thin films, three different types of conduction are present: a n-type surface layer conduction, a p-type bulk layer conduction channel, and a possible 2D surface state, as shown in Figure c. The α values are also consistent with previous descriptions of Sb 2 Te 3 thin films deposited on silicon-based substrates or in bulk form, with values of 0.6 and 0.01 having been obtained and its temperature dependences being influenced by transport disorder caused by the granular nature, in case of the thin films. , For the 300 nm thin film, the behavior is, however, different. The α values are small, indicating that the coherent conduction of the 2D state is overshadowed by the bulk layers semiconductor conduction.…”

Section: Resultssupporting

confidence: 89%

“…The α values are also consistent with previous descriptions of Sb 2 Te 3 thin films deposited on silicon-based substrates or in bulk form, with values of 0.6 and 0.01 having been obtained and its temperature dependences being influenced by transport disorder caused by the granular nature, in case of the thin films. 30,31 For the 300 nm thin film, the behavior is, however, different. The α values are small, indicating that the coherent conduction of the 2D state is overshadowed by the bulk layers semiconductor conduction.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Electronic Conduction Channels Engineered in Topological Insulator Sputtered Thin Films

Ferreira‐Teixeira

Vanstone

Pires

et al. 2022

ACS Appl. Electron. Mater.

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Sb 2 Te 3 is a topological insulator (TI) material that can be used in a wide range of applications from energy harvesting to Spin-Orbitronics. In this paper, the structural, electrical, and thermal transport properties of nanocrystalline ion beam sputtered Sb 2 Te 3 thin films were studied. Films with thicknesses between 35 and 300 nm, with nanocrystallites of sizes 10−20 nm, have a high resistivity between 0.072 and 2.03 Ω cm at 300 K, increasing with cooling. The Seebeck coefficient demonstrates the coexistence of n-type and p-type conduction, the latter being more prominent at high temperatures and in thicker films. The morphological and transport properties reveal that the films are constituted by two layers having different majority charge carriers, with the electronic bulk conduction being described by two semiconductor layers conducting in parallel, one p-type at the surface and another n-type, each described by an activation energy-dependent conductivity. Besides these bulk contributions, weak antilocalization (WAL) cusps are observed in the magnetoconductance below 10 K and at low magnetic fields. Analysis of the WAL hints that there is one twodimensional conduction channel open at low temperatures for the thinner films, whereas for the thicker film, this 2D conduction appears to be masked by the bulk channels. However, a magnetic localization length L Φ between 62 and 90 nm at 2 K is observed for all thin films. This behavior suggests that as the bulk activation energy conductions freeze out at low temperatures, the electrical conduction is carried by the supposed 2D state, which appears to have some of the features of a TI surface state. Through these measurements, we demonstrate that the type of dominant conduction can be controlled by the Sb 2 Te 3 film thickness in these large area sputtered films, while the conduction at low temperatures appears to be dominated by a robust TI state.

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Section: ■ Results and Discussionsupporting

confidence: 90%

Section: Resultssupporting

confidence: 89%

Section: ■ Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Electronic Conduction Channels Engineered in Topological Insulator Sputtered Thin Films

Ferreira‐Teixeira

Vanstone

Pires

et al. 2022

ACS Appl. Electron. Mater.

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“…36 Recently, Banerjee et al have reported the evidence for topological surface states in grainy topological insulator Bi 2 Se 3 through experimental observation 11 . Similarly, our earlier work 12 on Sb 2 Te 3 has also demonstrated a robust surface-state signature in nanobulk grainy materials.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Nevertheless, disorder present in dirty systems such as polycrystals, amorphous systems, and granular systems can hamper the 2D surface states due to domination of three-dimensional (3D) bulk states that can be tuned/controlled by optimizing the externally controllable parameters such as nanostructuring, size of nanocrystals, coupling between them, and so forth . Signatures of the emergence of macroscopic topological phases predicted theoretically and observed experimentally in amorphous and granular systems are reported in very few topological systems and, to the best of our knowledge, none in nano-TCI materials.…”

Section: Introductionmentioning

confidence: 93%

Two-Dimensional Weak Antilocalization Signatures Due to Quantum Coherent Transport in Nanocrystalline SnTe

et al. 2022

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Nanostructured topological crystalline insulators (TCIs) in the presence of exotic surface states with spin momentum locking reported in individual nanostructures are predicted to hold a great promise for spintronics and quantum computing applications. However, practical application demands a strategy with large-scale production and integration for device applications. In this work, we demonstrate through prominent signatures of weak antilocalization (WAL), arising predominantly from destructive quantum interference on robust surface states, that a correlated TCI phase is possible in the nanobulk assembly of carefully nanostructured quasi-two-dimensional SnTe (edge-to-edge length ∼ 382 nm) synthesized by a simple, rapid, and scalable microwave-assisted solvothermal method. Hikami–Larkin–Nagaoka analysis (T –0.71), as well as the temperature dependence of resistivity, illustrates an interplay of both conductions from 2D channels and 3D EEI effects as the precursor for the observed WAL at low temperatures (2–6 K). Interestingly, the enhanced thermoelectric power of the sample of ∼45 μV/K, with a p-type carrier concentration of ∼1018/cm3 at 300 K, makes this SnTe nanocrystalline assembly more attractive as a multifunctional material for large-scale technological applications.

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Charge Puddles Driven Complex Crossover of Magnetoresistance in Non‐Topological Sulfur Doped Antimony Selenide Nanowires

Kumar,

Venkatesh

2024

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A race to achieve a crossover from positive to negative magnetoresistance is intense in the field of nanostructured materials to reduce the size of memory devices. Here, the unusual complex magnetoresistance in nonmagnetic sulfur‐doped Sb2Se3 nanowires is demonstrated. Intentionally, sulfur is doped in such a way to nearly achieve the charge neutrality point that is evident from switching of carrier type from p‐type to n‐type at 13 K as inferred from the low‐temperature thermoelectric power measurements. A change from 3D variable range hopping (VRH) to power law transport with α = 0.18 in resistivity measurement signifies a Luttinger liquid transport with weak links through the nanowires. Interestingly, high magnetic field induced negative magnetoresistance (NMR) occurring in hole dominated temperature regimes can only be explained by invoking the concept of charge puddles. Spot energy dispersive spectroscopy (EDS), magnetic force microscopy (MFM) measurements, Tmott and Regel plot indicate an enhanced disorder in these sulfurized nanowires that are found to be the precursor for the formation of these charge puddles. Tunability of conducting states in these nanowires is investigated in the light of interplay of carrier type, magnetic field, temperature, and intricate intra‐inter wire transport that makes this nanowires potential for large scale spintronic devices.

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Weak antilocalization in Sb2Te3 nano-crystalline topological insulator

Cited by 16 publications

References 32 publications

Electronic Conduction Channels Engineered in Topological Insulator Sputtered Thin Films

Electronic Conduction Channels Engineered in Topological Insulator Sputtered Thin Films

Two-Dimensional Weak Antilocalization Signatures Due to Quantum Coherent Transport in Nanocrystalline SnTe

Charge Puddles Driven Complex Crossover of Magnetoresistance in Non‐Topological Sulfur Doped Antimony Selenide Nanowires

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