Density functional study of ternary topological insulator thin films

Chang, Jiwon; Register, Leonard F.; Banerjee, S.; Sahu, Bhagawan

doi:10.1103/physrevb.83.235108

Cited by 34 publications

(47 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The lattice parameters were determined to be a = 4.284Å, c = 29.669Å. The observed values are good agreement with those reported previously 17,27 .…”

Section: 26supporting

confidence: 79%

“…The observed values of α in literatures cover a wide range from -0.4 to -2.5, suggesting that it depends on (i) sample thickness 14,34 , (ii) presence of bulk conductivity gating 15,17,18 , and (iii) substrate. 33 The thin films of TIs, which have been prepared on substrate with different route, show the value of α around 0.5 18,33,35 .…”

Section: 33mentioning

confidence: 99%

“…Various strategies to improve surface conductivity, e.g., studying thin films or nano-flacks 6,[12][13][14][15][16] , gating 15,17,18 , and doping 10,11,19 have been employed. Among the all known TIs, the ternary tetradymite Bi 2 Te 2 Se (BTS) has largely been investigated material that gives excellent performance of surface in temperature dependence resistivity 6,[12][13][14][15][16]20 .…”

Section: -11mentioning

confidence: 99%

See 2 more Smart Citations

Evidence of surface transport and weak antilocalization in a single crystal of theBi2Te2Setopological insulator

et al. 2014

View full text Add to dashboard Cite

Topological insulators are known to their metallic surface states, a result of strong-spin-orbital coupling, that show unique surface transport phenomenon. But these surface transports are buried in presence of metallic bulk conduction. We synthesized very high quality Bi2Te2Se single crystals by modified Bridgman method, that possess high bulk resistivity of >20 Ωcm below 20 K, whereas the bulk is mostly inactive and surface transport dominates. Temperature dependence resistivity follows the activation law like a gap semiconductor in temperature range 20-300 K. We designed a special measurement geometry, which aims to extract the surface transport from the bulk. This special geometry is applied to measure the resistance and found that Bi2Te2Se single crystal exhibits a cross over from bulk to surface conduction at 20 K. Simultaneously, the material also shows strong evidence of weak anti-localization in magneto-transport due to the protection against scattering by conducting surface states. This novel simple geometry is an easy route to find the evidence of surface transport in topological insulators, which are the promising materials for future spintronic applications.Topological insulators (TIs) have recently attracted significant attention since they are materialized into a new state of quantum matters, and they possess topologically protected metallic states on their edges or surfaces.1,2 These conducting SSs originate from the inversion of bulk bands due to the results of strong-spin-orbital coupling. Therefore, these novel metallic states are a subject of intensive investigations because of not only its fundamental novelty but also its high potential applications for spintronics devices 3 and quantum computations. 4In 3D TIs, the topological surface states have been successfully investigated by surface-sensitive techniques as angle-resolved photoemission spectroscopy 5,6 and scanning tunneling microscopy 7,8 . However, the evidences of transport through the surface sates remain a challenge due to the presence of the parallel bulk conducting channels that usually dominate the transport properties. 9-11Various strategies to improve surface conductivity, e.g., studying thin films or nano-flacks 6,12-16 , gating 15,17,18 , and doping 10,11,19 have been employed. Among the all known TIs, the ternary tetradymite Bi 2 Te 2 Se (BTS) has largely been investigated material that gives excellent performance of surface in temperature dependence resistivity 6,[12][13][14][15][16]20 . It shows large bulk resistivity due to the nearly perfect crystalline structure, and it has been predicted nearly perfect Dirac cones in terms of less entanglement of bulk and surface states 6,16,19,20 . The quantum oscillations have also been observed in BTS 20-22 and doped BTS 10,19 bulk samples, and they show surfaceddominated transport contributes up to 70% of the total conductance 10,20 . Besides showing this metallic behavior, excellent performance of the surface states of TIs appears in magneto-conductance in effect of weak antiloca...

show abstract

“…The lattice parameters were determined to be a = 4.284Å, c = 29.669Å. The observed values are good agreement with those reported previously 17,27 .…”

Section: 26supporting

confidence: 79%

Section: 33mentioning

confidence: 99%

Section: -11mentioning

confidence: 99%

See 1 more Smart Citation

Evidence of surface transport and weak antilocalization in a single crystal of theBi2Te2Setopological insulator

et al. 2014

View full text Add to dashboard Cite

show abstract

“…185,[238][239][240][241][242][243] For Bi 2 Se 3 , it was shown by ARPES experiments 185,241) that this hybridization gap opens in ultrathin films with the thickness of 6 nm or less.…”

Section: Topological Protection Of the Surface Statementioning

confidence: 99%

Topological Insulator Materials

2013

View full text Add to dashboard Cite

Topological insulators represent a new quantum state of matter which is characterized by peculiar edge or surface states that show up due to a topological character of the bulk wave functions. This review presents a pedagogical account on topological insulator materials with an emphasis on basic theory and materials properties. After presenting a historical perspective and basic theories of topological insulators, it discusses all the topological insulator materials discovered as of May 2013, with some illustrative descriptions of the developments in materials discoveries in which the author was involved. A summary is given for possible ways to confirm the topological nature in a candidate material. Various synthesis techniques as well as the defect chemistry that are important for realizing bulk-insulating samples are discussed. Characteristic properties of topological insulators are discussed with an emphasis on transport properties. In particular, the Dirac fermion physics and the resulting peculiar quantum oscillation patterns are discussed in detail. It is emphasized that proper analyses of quantum oscillations make it possible to unambiguously identify surface Dirac fermions through transport measurements. The prospects of topological insulator materials for elucidating novel quantum phenomena that await discovery conclude the review.

show abstract

“…For the ternary TI Bi 2 Se 2 Te (Bi 2 Te 2 Se), we built thin-film structures with the bulk hexagonal unit-cell lattice parameters a = 0.422 nm (0.428 nm) and c = 2.92 nm (2.99 nm) in the previous theoretical calculation, 19 and optimized the thin-film structure by letting atoms move along the z direction. We optimized thin-film structures only for ternary TIs, since atomic relaxations significantly affect the band structure of thin-film Bi 2 Se 2 Te around the Dirac point.…”

Section: Isolated Thin Films and Computational Approachmentioning

confidence: 99%

Dielectric capping effects on binary and ternary topological insulator surface states

Chang

Jadaun

et al. 2011

Phys. Rev. B

Self Cite

View full text Add to dashboard Cite

Using a density-functional-based electronic structure method, we study the effect of crystalline dielectrics on the metallic surface states of Bismuth-and chalcogen-based binary and ternary three-dimensional topological insulator (TI) thin films. Crystalline quartz (SiO 2 ) and boron nitride (BN) dielectrics were considered. Crystalline approximation to the amorphous quartz allows one to study the effect of oxygen coverage or environmental effects on the surface-state degradation, which has gained attention recently in the experimental community. We considered both symmetric and asymmetric dielectric cappings to the surfaces of TI thin films. Our studies suggest that BN and quartz cappings have negligible effects on the Dirac cone surface states of both binary and ternary TIs, except in the case of an oxygen-terminated quartz surface. Dangling bond states of oxygens in oxygen-terminated quartz dominate the region close to Fermi level, thereby distorting the TI Dirac cone feature and burying the Dirac point in the quartz valence-band region. Passivating the oxygen-terminated surface with atomic hydrogen removes these dangling bond states from the Fermi-surface region, and consequently the clear Dirac cone is recovered. Our results are consistent with recent experimental studies of TI surface degradation in the presence of oxygen coverage.

show abstract

Density functional study of ternary topological insulator thin films

Cited by 34 publications

References 41 publications

Evidence of surface transport and weak antilocalization in a single crystal of theBi2Te2Setopological insulator

Evidence of surface transport and weak antilocalization in a single crystal of theBi2Te2Setopological insulator

Topological Insulator Materials

Dielectric capping effects on binary and ternary topological insulator surface states

Contact Info

Product

Resources

About