Pressure-induced topological phase transitions and structural transition in 1T-TiTe2 single crystal

Zhang, Min; Wang, Xiangqi; Rahman, Azizur; Zeng, Qunsong; Huang, Da; Dai, Rucheng; Wang, Zhongping; Zhang, Zengming

doi:10.1063/1.5012842

Cited by 33 publications

(21 citation statements)

References 34 publications

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“…The interest about TiTe 2 is continuously increasing in view of theoretical predictions and more recent experimental evidence about pressure induced topological phase transitions in TiTe 2 . The possibility to also manipulate superconductivity by external pressure as predicted and more recently evidenced in bulk TiTe 2 creates the prospect to explore the emergence of topological superconductivity in this material.…”

Section: Introductionmentioning

confidence: 99%

Room Temperature Commensurate Charge Density Wave in Epitaxial Strained TiTe₂ Multilayer Films

Fragkos

Sant

Alvarez

et al. 2019

Adv Materials Inter

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Despite a large number of studies [2,3] over the years since the first discovery [7] and a couple of comprehensive reviews [8,9] the actual mechanism for PLD/CDW formation is still under debate. The most recent experimental [10][11][12][13] and theoretical [14] works focus on the large area growth of the CDW phase [13] the thickness dependence, and the possible unconventional behavior in the ultimate 2D limit of a single layer TiSe 2 . [10][11][12]14] On the other hand, the other Ti dichalcogenides namely TiS 2 and TiTe 2 did not show any clear evidence until very recently when a CDW state was reported only for 1 monolayer (ML)-thin TiTe 2 at temperatures lower than 92 K. [15] It is surprising that the CDW in TiTe 2 was found to be totally suppressed for films thicker than 1 ML, [15] unlike the case of other TMDs where 1 ML and bulk-like films both make the transition to a CDW at nearly the same temperature.The interest about TiTe 2 is continuously increasing in view of theoretical predictions [16] and more recent experimental evidence [17] about pressure induced topological phase transitions in TiTe 2 . The possibility to also manipulate superconductivity by external pressure as predicted [18] and more recently evidenced [19] in bulk TiTe 2 creates the prospect to explore the emergence of topological superconductivity in this material. In the latter work [19] it has been shown that under nonhydrostatic pressure, a CDW-like state with estimated transition temperature above room temperature (RT) appears in bulk TiTe 2 at around 0.5-1.8 GPa. These results call for a re-examination of the possibility to obtain a CDW in multilayer TiTe 2 and indeed at RT with good potential for real world applications utilizing the properties of the CDW state. These applications include a voltage-controlled oscillator device operating at room temperature, [20] fast electronic resistance switching for nonvolatile memories, [21,22] and field-effect transistor devices potentially suitable for implementation of non-Boolean logic. [23] In this paper it is shown that multilayer films (50 ML ≈ 32 nm), as well as single layer TiTe 2 epitaxially grown on InAs(111)/ Si(111) substrates by molecular beam epitaxy exhibit, in ambient pressure conditions, a CDW distortion at room temperature which is sustained up to higher temperatures, at least 400 °C, as evidenced by reflection high energy electron diffraction (RHEED) ( Figure S1, Supporting Information). The results are explained in terms of anisotropic strain imposed by the substrate.The group IVB 2D transition metal dichalcogenides are considered to be stable in the high symmetry trigonal octahedral structure due to the lack of unpaired d-electrons on the metal site. It is found that multilayer epitaxial TiTe 2 is an exception adopting a commensurate 2 × 2 × 2 charge density wave (CDW) structure at room temperature with an ABA type of stacking as evidenced by direct lattice imaging and reciprocal space mapping. The CDW is stabilized by highly anisotropic strain imposed by the substrate with an...

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Section: Introductionmentioning

confidence: 99%

Room Temperature Commensurate Charge Density Wave in Epitaxial Strained TiTe₂ Multilayer Films

Fragkos

Sant

Alvarez

et al. 2019

Adv Materials Inter

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“…5, кривая 3). Эти особенности термоэлектрических свойств и производных dS/dP, связанные с топологическим ФП при 3−4 ГПа, сопровождаются переходом исходного сильного топологического изолятора с Z 2 -инвариантом v 0 = 1 в слабый с инвариантом v 0 = 0 в результате сжатия межщелевых пространств Ван-дер-Ваальса и ослабления связи между спином и импульсом [11,15].…”

Section: образцы для измерений и методика экспериментаunclassified

“…Одним из эффективных методов исследований топологических свойств материалов и их связи с кристаллической структурой вещества является метод внешнего давления в области электронных топологических фазовых переходов (ТФП). Анализ рамановского рассеяния, транспортных и термоэлектрических свойств при высоких давлениях в теллуриде висмута и некоторых твердых растворах показал перспективность использо-вания давления в области ТФП для повышения фактора мощности термоэлектриков за счет увеличения вклада топологических поверхностных состояний фермионов Дирака [8][9][10][11].…”

Section: Introductionunclassified

Фактор Мощности Твердых Растворов На Основе Теллурида Висмута В Области Топологических Фазовых Переходов При Высоких Давлениях

Коробейников¹,

Морозова²,

Лукьянова³

et al. 2019

Физика И Техника Полупроводников

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The Seebeck coefficient S and the electrical conductivity σ of solid solutions based on bismuth telluride with substitutions in Bi and Te sublattices were studied at pressures up to 12 GPa at room temperature. It is shown that with increasing pressure, the electrical conductivity increases and, despite the decrease in the Seebeck coefficient, an increase in the power factor (S^2)σ is observed in p-Bi0.5Sb1.5Te3 and n-Bi2Te1.65Se0.65S0.7 solid solutions. The maximum increase in the power factor was found for n-Bi2Te1.65Se0.65S0.7 in the pressure range of 3−4 GPa, corresponding to the electronic topological phase transition. The investigated solid solutions were used in the model of a thermoelectric module with adjustable mechanical stress applied to thermoelements.

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“…This research topic is closely related to applications since the discovery of new materials can lead to the development of new devices. Nowadays, there are many technological proposals based on topological materials [29][30][31] . The most prominent applications for TIs rely on their properties of carrying an electric current only at the edges or surfaces in two (2D) and three-dimensional (3D) case respectively, while the bulk remains an insulator 2,4 .…”

Section: Introductionmentioning

confidence: 99%

Anisotropic scaling in 3D topological models: fromWeyl semimetal to Hopf insulator

Rufo

Griffith

Lopes

et al. 2021

Preprint

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A proposal to study topological models beyond the standard topological classification and that exhibit breakdown of Lorentz invariance is presented. The focus of the investigation relies on their anisotropic quantum critical behavior. We study anisotropic effects on three-dimensional (3D) topological models, computing their anisotropic correlation length critical exponent ν obtained from numerical calculations of the penetration length of the zero-energy surface states as a function of the distance to the topological quantum critical point. A generalized Weyl semimetal model with broken time-reversal symmetry is introduced and studied using a modified Dirac equation. An approach to characterize topological surface states in topological insulators when applied to Fermi arcs allows to capture the anisotropic critical exponent θ = νx/νz. We also consider the Hopf insulator model, for which the study of the topological surface states yields unusual values for ν and for the dynamic critical exponent z. From an analysis of the energy dispersions, we propose a scaling relation να¯ zα¯ = 2q and θ = νx/νz = zz/zx for ν and z that only depends on the Hopf insulator Hamiltonian parameters p and q and the axis direction α¯ . An anisotropic quantum hyperscaling relation is also obtained.

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Pressure-induced topological phase transitions and structural transition in 1T-TiTe2 single crystal

Cited by 33 publications

References 34 publications

Room Temperature Commensurate Charge Density Wave in Epitaxial Strained TiTe₂ Multilayer Films

Room Temperature Commensurate Charge Density Wave in Epitaxial Strained TiTe₂ Multilayer Films

Фактор Мощности Твердых Растворов На Основе Теллурида Висмута В Области Топологических Фазовых Переходов При Высоких Давлениях

Anisotropic scaling in 3D topological models: fromWeyl semimetal to Hopf insulator

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Pressure-induced topological phase transitions and structural transition in 1T-TiTe2 single crystal

Cited by 33 publications

References 34 publications

Room Temperature Commensurate Charge Density Wave in Epitaxial Strained TiTe2 Multilayer Films

Room Temperature Commensurate Charge Density Wave in Epitaxial Strained TiTe2 Multilayer Films

Фактор Мощности Твердых Растворов На Основе Теллурида Висмута В Области Топологических Фазовых Переходов При Высоких Давлениях

Anisotropic scaling in 3D topological models: fromWeyl semimetal to Hopf insulator

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Product

Resources

About

Room Temperature Commensurate Charge Density Wave in Epitaxial Strained TiTe₂ Multilayer Films

Room Temperature Commensurate Charge Density Wave in Epitaxial Strained TiTe₂ Multilayer Films