Layer-dependent dielectric permittivity of topological insulator Bi2Se3 thin films

Fang, Mingsheng; Wang, Zhenyu; Gu, Honggang; Tong, Mingyu; Song, Baokun; Xie, Xuedong; Zhou, Tong; Chen, Xiuguo; Jiang, Hao; Jiang, Tian; Liu, Shiyuan

doi:10.1016/j.apsusc.2019.144822

Cited by 33 publications

(19 citation statements)

References 52 publications

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“…At present, SE measurements is often used to study the optical properties of thin film materials or largesize bulk materials. [40][41][42] Schematic image of Mueller matrix SE measurements is shown in Figure S3, Supporting Information. The SE measures the complete Mueller matrix of the sample based on the dual-rotating compensator principle.…”

Section: Birefringence and Dichroism Of Tis 3 And Zrsmentioning

confidence: 99%

Birefringence and Dichroism in Quasi‐1D Transition Metal Trichalcogenides: Direct Experimental Investigation

Hou

Guo

Yang

et al. 2021

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Birefringence and dichroism are very important properties in optical anisotropy. Understanding the intrinsic birefringence and dichroism of a material can provide great help to utilize its optical anisotropy. But the direct experimental investigation of birefringence in nanoscale materials is rarely reported. As typical anisotropic transition metals trichalcogenides (TMTCs) materials with quasi‐1D structure, TiS3 and ZrS3 have attracted extensive attention due to their special crystal structure and optical anisotropy characteristics. Here, the optical anisotropy properties such as birefringence and dichroism of two kinds of quasi‐1D TMTCs, TiS3 and ZrS3, are theoretically and experimentally studied. In experimental results, the anisotropic refraction and anisotropic reflection of TiS3 and ZrS3 are studied by polarization‐resolved optical microscopy and azimuth‐dependent reflectance difference microscopy, respectively. In addition, the birefringence and dichroism of ZrS3 nanoribbon in experiment are directly measured by spectrometric ellipsometry measurements, and a reasonable result is obtained. This work provides the basic optical anisotropy information of TiS3 and ZrS3. It lays a foundation for the further study of the optical anisotropy of these two materials and provides a feasible method for the study of birefringence and dichroism of other nanomaterials in the future.

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Section: Birefringence and Dichroism Of Tis 3 And Zrsmentioning

confidence: 99%

Birefringence and Dichroism in Quasi‐1D Transition Metal Trichalcogenides: Direct Experimental Investigation

Hou

Guo

Yang

et al. 2021

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“…[11][12][13] Also, for spintronic and thermoelectric applications, property changes with thickness are reported in topologically insulating Bismuth chalcogenides. [14][15][16][17][18][19][20] Yet, we are not aware of studies which compare the thickness dependence of physical properties for the two different solid states of chalcogenide materials. Could it be that there is a difference in the thickness dependence of material properties for a given compound in its amorphous and crystalline phase?…”

Section: Introductionmentioning

confidence: 99%

Scaling and Confinement in Ultrathin Chalcogenide Films as Exemplified by GeTe

Kerres

Zhou

Vaishnav

et al. 2022

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Chalcogenides such as GeTe, PbTe, Sb2Te3, and Bi2Se3 are characterized by an unconventional combination of properties enabling a plethora of applications ranging from thermo‐electrics to phase change materials, topological insulators, and photonic switches. Chalcogenides possess pronounced optical absorption, relatively low effective masses, reasonably high electron mobilities, soft bonds, large bond polarizabilities, and low thermal conductivities. These remarkable characteristics are linked to an unconventional bonding mechanism characterized by a competition between electron delocalization and electron localization. Confinement, that is, the reduction of the sample dimension as realized in thin films should alter this competition and modify chemical bonds and the resulting properties. Here, pronounced changes of optical and vibrational properties are demonstrated for crystalline films of GeTe, while amorphous films of GeTe show no similar thickness dependence. For crystalline films, this thickness dependence persists up to remarkably large thicknesses above 15 nm. X‐ray diffraction and accompanying simulations employing density functional theory relate these changes to thickness dependent structural (Peierls) distortions, due to an increased electron localization between adjacent atoms upon reducing the film thickness. A thickness dependence and hence potential to modify film properties for all chalcogenide films with a similar bonding mechanism is expected.

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“…Furthermore, the sample thickness needs to be known in advance when dealing with opaque samples. Another method is using spectroscopic ellipsometry especially Mueller matrix spectroscopic ellipsometry (MMSE), , which determines the complete dielectric tensor by fitting the measured ellipsometric spectra with a well-built optical model. , With this powerful method, we comprehensively and quantitatively discuss the optical anisotropy in novel materials, such as the birefringence, dichroism, and optical activity, from the complete dielectric tensor and further deeply reveal the underlying physical mechanisms combined with first-principle calculations. ,, …”

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confidence: 99%

“…Hence, the excitonic effect probably has negligible influence on the dielectric functions of ZrTe 5 in our experiment. J cv is the joint density of states involved in the interband transition and can be expressed as , where S is the constant energy surface defined by E cv = E , and ∇ k ( E cv ) is the gradient in the k -space. Obviously, if the gradient ∇ k ( E cv ) approaches zero, the contribution of J cv to ε i approaches infinity.…”

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confidence: 99%

“…The energy differences between the conduction and valence bands E cv can be treated as a bridge to connect the CPs with the band structure and PDOS, which helps to explore the origin of CPs. , To further identify the specific bands and carrier types involved in the optical transitions at the CPs, we calculated the band structure as well as the PDOS by the first-principle calculations, as given in Figure b,d,f.…”

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Complete Dielectric Tensor and Giant Optical Anisotropy in Quasi-One-Dimensional ZrTe₅

Guo

Fang

et al. 2021

ACS Materials Lett.

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Anisotropy in low-dimensional materials offers an extra degree of freedom to understand and tune the peculiar or potential properties to design novel electronic, optical, thermal, and optoelectronic devices. However, most research attention has been paid to qualitatively observing anisotropic phenomena, lacking quantitatively revealing optical anisotropy, in particular, and deeply digging for the physical mechanism. In this work, for the first time to our knowledge, the complete dielectric tensor of quasi-one-dimensional ZrTe5 is determined by Mueller matrix spectroscopic ellipsometry (MMSE) to quantitatively and comprehensively investigate the giant optical anisotropy, and the underlying physical mechanism is revealed by combination with the first-principle calculations. The ZrTe5 demonstrates giant dispersive birefringence and dichroism, and the birefringence (Δn = 0.58) outperforms many other low-dimensional and conventional birefringent materials, showing great potential and advantages in fabricating miniature and integrated polarization-sensitive devices. By combining the critical point (CP) analysis and first-principle calculations, the specific interband transitions related to the CPs in dielectric function spectra along three crystal axes of ZrTe5 are identified, revealing the physical essence of the optical anisotropy from the perspective of quantum mechanics. The proposed method is general and can be easily extended to quantitatively investigate the optical anisotropies in other novel low-symmetry materials.

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Layer-dependent dielectric permittivity of topological insulator Bi2Se3 thin films

Cited by 33 publications

References 52 publications

Birefringence and Dichroism in Quasi‐1D Transition Metal Trichalcogenides: Direct Experimental Investigation

Birefringence and Dichroism in Quasi‐1D Transition Metal Trichalcogenides: Direct Experimental Investigation

Scaling and Confinement in Ultrathin Chalcogenide Films as Exemplified by GeTe

Complete Dielectric Tensor and Giant Optical Anisotropy in Quasi-One-Dimensional ZrTe₅

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Layer-dependent dielectric permittivity of topological insulator Bi2Se3 thin films

Cited by 33 publications

References 52 publications

Birefringence and Dichroism in Quasi‐1D Transition Metal Trichalcogenides: Direct Experimental Investigation

Birefringence and Dichroism in Quasi‐1D Transition Metal Trichalcogenides: Direct Experimental Investigation

Scaling and Confinement in Ultrathin Chalcogenide Films as Exemplified by GeTe

Complete Dielectric Tensor and Giant Optical Anisotropy in Quasi-One-Dimensional ZrTe5

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Product

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Complete Dielectric Tensor and Giant Optical Anisotropy in Quasi-One-Dimensional ZrTe₅