Circular Photogalvanic Effect in Oxide Two-Dimensional Electron Gases

Wang, Shuanhu; Zhang, Hui; Zhang, Jine; Li, Shuqin; Luo, Dianbing; Wang, Jianyuan; Kusaka, Jin; Sun, J. R.

doi:10.1103/physrevlett.128.187401

Cited by 18 publications

(11 citation statements)

References 33 publications

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“…As mentioned above, despite the large number of publications on the topic of generation of polarization-sensitive transverse photocurrent in various materials, arising by various mechanisms, such a phenomenon has not been observed before. It is possible that this is due to the fact that in many studies of the transverse photocurrent, cw laser radiation or nanosecond laser radiation has been used (see, for example, [33,[67][68][69]).…”

Section: Resultsmentioning

confidence: 99%

Incident Angle Dependence of the Waveform of the Polarization-Sensitive Photoresponse in CuSe/Se Thin Film

et al. 2022

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The results of studying the waveforms of longitudinal and transverse photocurrent pulses generated in thin, semitransparent CuSe/Se films as a function of the angle of incidence (α) of a femtosecond laser beam at linear and circular polarizations are presented. It has been established that the durations of unipolar longitudinal photocurrent pulses at linear and circular polarizations of laser pumping do not depend on the angle α. It is shown that the evolution of the temporal profile of the helicity-sensitive transverse photocurrent with a change in α strongly depends on polarization. At linear polarization, the shape of the unipolar pulses remains virtually constant; however, at circular polarization, the generation of unipolar and bipolar pulses is possible, with the waveforms strongly depending on the angle α. The influence of the incidence angle on the waveforms of transverse photocurrent pulses is explained by the transformation of linear and circular polarization into an elliptical upon the refraction of light at the air/semitransparent film interface and by the interplay of photocurrents arising due to linear and circular surface photogalvanic effects in the film. The presented findings can be utilized to develop polarization and incidence angle-sensitive photovoltaic devices.

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Section: Resultsmentioning

confidence: 99%

Incident Angle Dependence of the Waveform of the Polarization-Sensitive Photoresponse in CuSe/Se Thin Film

et al. 2022

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“…The unique radial spin texture originates from the low symmetry of the crystal structure and the strong spin–orbit coupling (SOC) of Te atoms, reflected in the k linear term of the conduction band Hamiltonian H false( k false) = ℏ 2 k ∥ 2 2 m ∥ + ℏ 2 k ⊥ 2 2 m ⊥ + ℏ v ∥ k ∥ σ z + ℏ v ⊥ false( k x σ x + k y σ y false) (eq ). The Weyl-type SOC-induced radial spin texture is different from that in the surface state of topological insulators − (Figure e, spin-polarization direction perpendicular to the electron momentum direction) or the Rashba SOC of semiconductor interfaces (Figure f, spin-polarization direction perpendicular to the electron momentum direction, and two Fermi surfaces with opposite contribution). The left- and right-circular-polarized light with negative and positive angular momentum selectively excite electrons with opposite spin polarizations according to angular momentum conservation.…”

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confidence: 89%

“…(eq 1). The Weyl-type SOC-induced 19 radial spin texture is different from that in the surface state of topological insulators 20−22 (Figure 1e, spin-polarization direction perpendicular to the electron momentum direction) or the Rashba SOC of semiconductor interfaces 23 (Figure 1f, spin-polarization direction perpendicular to the electron momentum direction, and two Fermi surfaces with opposite contribution).…”

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confidence: 90%

Tunable Circular Photogalvanic and Photovoltaic Effect in 2D Tellurium with Different Chirality

et al. 2023

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Chirality arises from the asymmetry of materials, where two counterparts are the mirror image of each other. The interaction between circular-polarized light and quantum materials is enhanced in chiral space groups due to the structural chirality. Tellurium (Te) possesses the simplest chiral crystal structure, with Te atoms covalently bonded into a spiral atomic chain (left-or right-handed) with a periodicity of 3. Here, we investigate the tunable circular photoelectric responses in 2D Te field-effect transistors with different chirality, including the longitudinal circular photogalvanic effect induced by the radial spin texture (electron-spin polarization parallel to the electron momentum direction) and the circular photovoltaic effect induced by the chiral crystal structure (helical Te atomic chains). Our work demonstrates the controllable manipulation of the chirality degree of freedom in materials.

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“…LPGE can arise from the asymmetric scattering of free carriers by phonons, static defects, or other carriers in noninversion symmetric systems, [ 33 ] and may be related to the origin of topological surface states. [ 31 ] So far, CPGE has been studied in strong SOC systems, such as 2D electron gas, [ 34 ] Weyl semimetals, [ 35 ] topological insulators, [ 31,33,36 ] etc. With the coexistence of TCI and TI surface states on one facet in N ‐dependent TSLs, there may be interesting photogalvanic effects awaiting exploration.…”

Section: Formation Of Dual Tsls and Arpes Measurementsmentioning

confidence: 99%

Dual Topology of Dirac Electron Transport and Photogalvanic Effect in Low‐Dimensional Topological Insulator Superlattices

et al. 2023

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are protected by time-reversal symmetry (TRS) and characterized by a nonzero Z 2 invariant. [1] The spin and momentum of topological edge states (2D TIs) or surface states (3D TIs) are orthogonally locked and robust against nonmagnetic backscattering. [2] Beyond the Z 2 -order protected band topology, the crystalline symmetry preserves the band topology in cases such as discrete rotation and mirror symmetry which defines the topological crystalline insulators (TCIs). [3] A combination of these two topological properties in one material, i.e., dual topology, defines a dual TI and offers fertile possibilities of gapping one topological surface state via breaking the respective symmetry while preserving another. [4] Therefore, the exploration of dual TIs can elucidate more degrees of freedom to manipulate the band structure and electric transport properties for designing novel topological electronic, spintronic, thermoelectric, and optical devices. [5] Dual TIs can exist in different topological forms. [6] One form refers to dual protection of surface states by multiple bulk symmetries, such as Bi 2 Te 3 [6b] predicted to be both a TI and a TCI whose topological surface state is protected by TRS and crystal symmetry simultaneously. Another interesting form is that the dual TIs can Dual topological insulators, simultaneously protected by time-reversal symmetry and crystalline symmetry, open great opportunities to explore different symmetry-protected metallic surface states. However, the conventional dual topological states located on different facets hinder integration into planar opto-electronic/spintronic devices. Here, dual topological superlattices (TSLs) Bi 2 Se 3 -(Bi 2 /Bi 2 Se 3 ) N with limited stacking layer number N are constructed. Angle-resolved photoelectron emission spectra of the TSLs identify the co existence and adjustment of dual topological surface states on Bi 2 Se 3 facet. The existence and tunability of spin-polarized dual-topological bands with N on Bi 2 Se 3 facet result in an unconventionally weak antilocalization effect (WAL) with variable WAL coefficient α (maximum close to 3/2) from quantum transport experiments. Most importantly, it is identified that the spin-polarized surface electrons from dual topological bands exhibit circularly and linearly polarized photogalvanic effect (CPGE and LPGE). It is anticipated that the stacked dual-topology and stacking layer number controlled bands evolution provide a platform for realizing intrinsic CPGE and LPGE. The results show that the surface electronic structure of the dual TSLs is highly tunable and well-regulated for quantum transport and photoexcitation, which shed light on engineering for opto-electronic/spintronic applications.

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Circular Photogalvanic Effect in Oxide Two-Dimensional Electron Gases

Cited by 18 publications

References 33 publications

Incident Angle Dependence of the Waveform of the Polarization-Sensitive Photoresponse in CuSe/Se Thin Film

Incident Angle Dependence of the Waveform of the Polarization-Sensitive Photoresponse in CuSe/Se Thin Film

Tunable Circular Photogalvanic and Photovoltaic Effect in 2D Tellurium with Different Chirality

Dual Topology of Dirac Electron Transport and Photogalvanic Effect in Low‐Dimensional Topological Insulator Superlattices

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