Ellipsometric study on temperature dependent optical properties of topological bismuth film

Lu, Yang; Zheng, Yu‐Xiang; Yang, Shang-Dong; Liu, Zhun-Hua; Zhang, Jinbo; Zhang, Rongjun; Wang, Song-You; Zhang, Dongxu; Chen, Liang‐Yao

doi:10.1016/j.apsusc.2016.11.006

Cited by 11 publications

(16 citation statements)

References 37 publications

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“…Since the band overlaps are rather small, only subtle changes in the electronic band structure can cause a tremendous change in its electrical and optical properties. Furthermore, not only is atomic displacement reported to increase available carrier density [13] , but also both amorphous and liquid state are reported to have a metallic character with much higher free carrier concentration [15,16] . In the next subsection we will discuss in more detail how these structural and electronic changes affect the optical response.…”

Section: Structural Distortions In Bi Induced By High Power Laser Irrmentioning

confidence: 99%

“…In the case of disordered Bi, it is expected that it becomes more metallic in nature as its amorphousness or disorder increases [13,15] . The droplets would then share similarities partly with amorphous and liquid Bi, which both have much higher density of carriers and are metallic in nature [15,16] .…”

Section: Laser Induced Optical Phase Change In Bimentioning

confidence: 99%

“…Another similarity between amorphous and liquid Bi, is that their optical response (dielectric function/permittivity) can be described by the Drude model [15,16] , meaning that the free carriers are dominating the materials response to electromagnetic radiation. Regarding metal-liquid transition of Bi, a recent report shown that at the transition from solid to liquid phase, the real part of the dielectric function (ε1) becomes more negative and the imaginary part (ε2) increases [16] .…”

Section: Laser Induced Optical Phase Change In Bimentioning

confidence: 99%

“…amorphous state, the available free carrier density is four-orders of magnitude greater than the ordered crystalline semimetal Bi [15] . The amorphous Bi shares similar characteristics with its liquid state in terms of its electrical and optical response, and has roughly the same free carrier density and a more metallic character compared to the ordinary A7 crystalline structure [15,16]. Transitions like these can also be induced through chemical methods.…”

Section: Introductionmentioning

confidence: 99%

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Optical phase change in bismuth through structural distortions induced by laser irradiation

Handegård

Kitajima

Nagao

2020

Radiation Effects and Defects in Solids

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Semimetal Bismuth (Bi) is known to posess a wide range of peculiar properties, owing to its unique electronic band structure. Its electronic band can easily be distorted by structural changes, and thereby undergo transitions between semimetal to either semiconductor or metal states.Utilizing a focused laser beam, one can easily introduce structural defects, along with phase changes, oxidation, and morphological modifications. Confocal Raman microscopy indicated that the as-fabricated Bi droplets inhibit the Raman signal from the underlying silicon (Si) substrate.After a laser flash heating step, the intensity of Si optical phonons was strongly enhanced at the positions of Bi droplets, and exceeding the intensity from the bare Si substrate. Thus, such laser irradiating step on the Bi droplets induces an optical phase change. The optical phase change was detected as going from inhibition to strong enhancement of the underlying Si substrate Raman signal. From the observed Bi optical phonon modes (Eg and A1g), alterations in the Raman peaks due to laser exposure indicated that the ordered crystallinity in pristine Bi droplets became deteriorated. The effects of atomic displacements and loss of structural order in Bi droplets impacts its dielectric response. The observed Si Raman signal enhancement is similar to the surfaceenhanced Raman scattering effect typically known for noble metals.

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Section: Structural Distortions In Bi Induced By High Power Laser Irrmentioning

confidence: 99%

Section: Laser Induced Optical Phase Change In Bimentioning

confidence: 99%

Section: Laser Induced Optical Phase Change In Bimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Optical phase change in bismuth through structural distortions induced by laser irradiation

Handegård

Kitajima

Nagao

2020

Radiation Effects and Defects in Solids

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show abstract

“…Thus, a change in the crystal lattice of Bi can have considerable effects on its electrical-and optical conductivity. The amorphous structure of Bi has many similar features to its liquid state in terms of its electrical and optical response, and has greater metallic character [10]. The microscopic mechanism for this behavior is an intriguing subject in condensed matter physics and of technical importance for engineering applications in thermal and optoelectronic devices.…”

Section: Introductionmentioning

confidence: 99%

Laser-induced structural disordering and optical phase change in semimetal bismuth observed by Raman microscopy

Handegård

Kitajima

Nagao

2019

Applied Surface Science

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We observed strong enhancement of the Raman signal from a silicon (Si) substrate hidden beneath nano/micro-droplets of bismuth (Bi) after exposing them to a high-power laser beam (785 nm). Confocal Raman microscopy indicated that the as-fabricated Bi droplets inhibit the Raman signal from the underlying Si substrate. After the laser flash heating step, the intensity of Si optical phonons was strongly enhanced at the positions of Bi droplets, becoming even more intense than that of the bare Si substrate. Analyses of the Bi optical phonon modes, Eg and A1g, confirmed a loss of long-range ordered crystallinity in the laser exposed droplets. Such lattice disordering can increase the available free carrier density in semimetal Bi, as occurs in the case of its amorphous and liquid states. And this can induce an optical phase change, which causes a marked enhancement of Si Raman signals through an effect similar to surface-enhanced Raman scattering (SERS).

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Effects of oblique angle deposition on structural, electrical and wettability properties of Bi thin films grown by thermal evaporation

Jain

Kaur

Arora

et al. 2019

Applied Surface Science

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Ellipsometric study on temperature dependent optical properties of topological bismuth film

Cited by 11 publications

References 37 publications

Optical phase change in bismuth through structural distortions induced by laser irradiation

Optical phase change in bismuth through structural distortions induced by laser irradiation

Laser-induced structural disordering and optical phase change in semimetal bismuth observed by Raman microscopy

Effects of oblique angle deposition on structural, electrical and wettability properties of Bi thin films grown by thermal evaporation

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