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Bianca G, Trovatello C, Zilli A, Zappia MI, Bellani S, Curreli N, Conticello I, Buha J, Piccinni M, Ghini M, Celebrano M, Finazzi M, Kriegel I, Antonatos N, Sofer Z, Bonaccorso F. Liquid-Phase Exfoliation of Bismuth Telluride Iodide (BiTeI): Structural and Optical Properties of Single-/Few-Layer Flakes. ACS Appl Mater Interfaces 2022; 14:34963-34974. [PMID: 35876692 PMCID: PMC9354013 DOI: 10.1021/acsami.2c07704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
Bismuth telluride halides (BiTeX) are Rashba-type crystals with several potential applications ranging from spintronics and nonlinear optics to energy. Their layered structures and low cleavage energies allow their production in a two-dimensional form, opening the path to miniaturized device concepts. The possibility to exfoliate bulk BiTeX crystals in the liquid represents a useful tool to formulate a large variety of functional inks for large-scale and cost-effective device manufacturing. Nevertheless, the exfoliation of BiTeI by means of mechanical and electrochemical exfoliation proved to be challenging. In this work, we report the first ultrasonication-assisted liquid-phase exfoliation (LPE) of BiTeI crystals. By screening solvents with different surface tension and Hildebrandt parameters, we maximize the exfoliation efficiency by minimizing the Gibbs free energy of the mixture solvent/BiTeI crystal. The most effective solvents for the BiTeI exfoliation have a surface tension close to 28 mN m-1 and a Hildebrandt parameter between 19 and 25 MPa0.5. The morphological, structural, and chemical properties of the LPE-produced single-/few-layer BiTeI flakes (average thickness of ∼3 nm) are evaluated through microscopic and optical characterizations, confirming their crystallinity. Second-harmonic generation measurements confirm the non-centrosymmetric structure of both bulk and exfoliated materials, revealing a large nonlinear optical response of BiTeI flakes due to the presence of strong quantum confinement effects and the absence of typical phase-matching requirements encountered in bulk nonlinear crystals. We estimated a second-order nonlinearity at 0.8 eV of |χ(2)| ∼ 1 nm V-1, which is 10 times larger than in bulk BiTeI crystals and is of the same order of magnitude as in other semiconducting monolayers (e.g., MoS2).
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Affiliation(s)
- Gabriele Bianca
- Graphene
Labs, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
- Dipartimento
di Chimica e Chimica Industriale, Università
degli Studi di Genova, via Dodecaneso 31, 16146 Genoa, Italy
| | - Chiara Trovatello
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Attilio Zilli
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Marilena Isabella Zappia
- BeDimensional
S.p.A., via Lungotorrente
Secca 30R, 16163 Genova, Italy
- Department
of Physics, University of Calabria, Via P. Bucci cubo 31/C Rende, Cosenza 87036, Italy
| | | | - Nicola Curreli
- Functional
Nanosystems, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genova, Italy
| | - Irene Conticello
- BeDimensional
S.p.A., via Lungotorrente
Secca 30R, 16163 Genova, Italy
| | - Joka Buha
- Nanochemistry
Department, Istituto Italiano di Tecnologia, via Morego 30, Genova 16163, Italy
| | - Marco Piccinni
- Graphene
Labs, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
- Dipartimento
di Chimica e Chimica Industriale, Università
degli Studi di Genova, via Dodecaneso 31, 16146 Genoa, Italy
| | - Michele Ghini
- Functional
Nanosystems, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genova, Italy
| | - Michele Celebrano
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Marco Finazzi
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Ilka Kriegel
- Functional
Nanosystems, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genova, Italy
| | - Nikolas Antonatos
- Department
of Inorganic Chemistry, University of Chemistry
and Technology Prague, Technická 5, 16628 Prague 6, Czech Republic
| | - Zdeněk Sofer
- Department
of Inorganic Chemistry, University of Chemistry
and Technology Prague, Technická 5, 16628 Prague 6, Czech Republic
| | - Francesco Bonaccorso
- Graphene
Labs, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
- BeDimensional
S.p.A., via Lungotorrente
Secca 30R, 16163 Genova, Italy
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VanGennep D, Jackson DE, Graf D, Berger H, Hamlin JJ. Evolution of the Fermi surface of BiTeCl with pressure. J Phys Condens Matter 2017; 29:295702. [PMID: 28513467 DOI: 10.1088/1361-648x/aa73b7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report measurements of Shubnikov-de Haas oscillations in the giant Rashba semiconductor BiTeCl under applied pressures up to ∼2.5 GPa. We observe two distinct oscillation frequencies, corresponding to the Rashba-split inner and outer Fermi surfaces. BiTeCl has a conduction band bottom that is split into two sub-bands due to the strong Rashba coupling, resulting in two spin-polarized conduction bands as well as a Dirac point. Our results suggest that the chemical potential lies above this Dirac point, giving rise to two Fermi surfaces. We use a simple two-band model to understand the pressure dependence of our sample parameters. Comparing our results on BiTeCl to previous results on BiTeI, we observe similar trends in both the chemical potential and the Rashba splitting with pressure.
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Affiliation(s)
- D VanGennep
- Department of Physics, University of Florida, Gainesville, FL 32611, United States of America
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VanGennep D, Linscheid A, Jackson DE, Weir ST, Vohra YK, Berger H, Stewart GR, Hennig RG, Hirschfeld PJ, Hamlin JJ. Pressure-induced superconductivity in the giant Rashba system BiTeI. J Phys Condens Matter 2017; 29:09LT02. [PMID: 28004645 DOI: 10.1088/1361-648x/aa5567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
At ambient pressure, BiTeI exhibits a giant Rashba splitting of the bulk electronic bands. At low pressures, BiTeI undergoes a transition from trivial insulator to topological insulator. At still higher pressures, two structural transitions are known to occur. We have carried out a series of electrical resistivity and AC magnetic susceptibility measurements on BiTeI at pressure up to ∼40 GPa in an effort to characterize the properties of the high-pressure phases. A previous calculation found that the high-pressure orthorhombic P4/nmm structure BiTeI is a metal. We find that this structure is superconducting with T c values as high as 6 K. AC magnetic susceptibility measurements support the bulk nature of the superconductivity. Using electronic structure and phonon calculations, we compute T c and find that our data is consistent with phonon-mediated superconductivity.
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Affiliation(s)
- D VanGennep
- Department of Physics, University of Florida, Gainesville, FL 32611, United States of America
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Park J, Jin KH, Jo YJ, Choi ES, Kang W, Kampert E, Rhyee JS, Jhi SH, Kim JS. Quantum Oscillation Signatures of Pressure-induced Topological Phase Transition in BiTeI. Sci Rep 2015; 5:15973. [PMID: 26522628 DOI: 10.1038/srep15973] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 10/07/2015] [Indexed: 11/09/2022] Open
Abstract
We report the pressure-induced topological quantum phase transition of BiTeI single crystals using Shubnikov-de Haas oscillations of bulk Fermi surfaces. The sizes of the inner and the outer FSs of the Rashba-split bands exhibit opposite pressure dependence up to P = 3.35 GPa, indicating pressure-tunable Rashba effect. Above a critical pressure P ~ 2 GPa, the Shubnikov-de Haas frequency for the inner Fermi surface increases unusually with pressure, and the Shubnikov-de Haas oscillations for the outer Fermi surface shows an abrupt phase shift. In comparison with band structure calculations, we find that these unusual behaviors originate from the Fermi surface shape change due to pressure-induced band inversion. These results clearly demonstrate that the topological quantum phase transition is intimately tied to the shape of bulk Fermi surfaces enclosing the time-reversal invariant momenta with band inversion.
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Xi X, He XG, Guan F, Liu Z, Zhong RD, Schneeloch JA, Liu TS, Gu GD, Du X, Chen Z, Hong XG, Ku W, Carr GL. Bulk signatures of pressure-induced band inversion and topological phase transitions in Pb(1-x)Sn(x)Se. Phys Rev Lett 2014; 113:096401. [PMID: 25215996 DOI: 10.1103/physrevlett.113.096401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Indexed: 06/03/2023]
Abstract
The characteristics of topological insulators are manifested in both their surface and bulk properties, but the latter remain to be explored. Here we report bulk signatures of pressure-induced band inversion and topological phase transitions in Pb(1-x)Sn(x)Se (x=0.00, 0.15, and 0.23). The results of infrared measurements as a function of pressure indicate the closing and the reopening of the band gap as well as a maximum in the free carrier spectral weight. The enhanced density of states near the band gap in the topological phase gives rise to a steep interband absorption edge. The change of density of states also yields a maximum in the pressure dependence of the Fermi level. Thus, our conclusive results provide a consistent picture of pressure-induced topological phase transitions and highlight the bulk origin of the novel properties in topological insulators.
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Affiliation(s)
- Xiaoxiang Xi
- Photon Sciences, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Xu-Gang He
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA and Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA
| | - Fen Guan
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA
| | - Zhenxian Liu
- Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015, USA
| | - R D Zhong
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - J A Schneeloch
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - T S Liu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA and School of Chemical Engineering and Environment, North University of China, Taiyuan 030051, China
| | - G D Gu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | | | - Z Chen
- Department of Geosciences, Stony Brook University, Stony Brook, New York 11794, USA
| | - X G Hong
- Department of Geosciences, Stony Brook University, Stony Brook, New York 11794, USA
| | - Wei Ku
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - G L Carr
- Photon Sciences, Brookhaven National Laboratory, Upton, New York 11973, USA
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