Spatially dispersive circular photogalvanic effect in a Weyl semimetal

Ji, Zhurun; Liu, Gerui; Addison, Zachariah; Liu, Wenjing; Yu, Peng; Gao, Heng; Liu, Zheng; Rappe, Andrew M.; Kane, C. L.; Mele, E. J.; Agarwal, Ritesh

doi:10.1038/s41563-019-0421-5

Cited by 135 publications

(110 citation statements)

References 46 publications

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“…In addition, note that the performance of the studied device is mainly limited by the structure of antenna, with substantial potential improvements possible by the exploration of wavelength-matched structures. In addition, it is particularly attractive to substantiate the topological nature of Bloch wave functions at Weyl nodes through inversion symmetry breaking, with the involvement of divergent Berry curvature dipole or skew scattering for high-frequency rectifier (38). Even so, our device is already exploitable for high-resolution terahertz transmission imaging benefiting from the fast response, high stability, and broadband nature.…”

Section: Terahertz Detection and Imaging Applications Under Electricamentioning

confidence: 99%

Anisotropic ultrasensitive PdTe ₂ -based phototransistor for room-temperature long-wavelength detection

Guo

Chen

et al. 2020

Sci. Adv.

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Emergent topological Dirac semimetals afford fresh pathways for optoelectronics, although device implementation has been elusive to date. Specifically, palladium ditelluride (PdTe2) combines the capabilities provided by its peculiar band structure, with topologically protected electronic states, with advantages related to the occurrence of high-mobility charge carriers and ambient stability. Here, we demonstrate large photogalvanic effects with high anisotropy at terahertz frequency in PdTe2-based devices. A responsivity of 10 A/W and a noise-equivalent power lower than 2 pW/Hz0.5 are achieved at room temperature, validating the suitability of PdTe2-based devices for applications in photosensing, polarization-sensitive detection, and large-area fast imaging. Our findings open opportunities for exploring uncooled and sensitive photoelectronic devices based on topological semimetals, especially in the highly pursuit terahertz band.

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Section: Terahertz Detection and Imaging Applications Under Electricamentioning

confidence: 99%

Anisotropic ultrasensitive PdTe ₂ -based phototransistor for room-temperature long-wavelength detection

Guo

Chen

et al. 2020

Sci. Adv.

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“…The in-plane CPGE under oblique or normal incidence has been studied in a wide range of materials [31][32][33][52][53][54][55][56][57][58][59]. Any intrinsic CPGE requires the material to be inversion breaking [31][32][33][49][50][51][52][53][54][55][56][57][58][59]. [50] Hosur, P. Circular photogalvanic effect on topological insulator surfaces: Berry-curvature- There are three inequivalent L points (L 1 , L 2 and L 3 ).…”

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confidence: 99%

Spontaneous gyrotropic electronic order in a transition-metal dichalcogenide

Gao

et al. 2020

Nature

101

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2The observation of chirality is ubiquitous in nature. Contrary to intuition, the population of opposite chiralities is surprisingly asymmetric at fundamental levels [1,2]. Examples range from parity violation in the subatomic weak force [1] to the homochirality in essential biomolecules [2]. The ability to achieve chiralityselective synthesis (chiral induction) is of great importance in stereochemistry, molecular biology and pharmacology [2]. In condensed matter physics, a crystalline electronic system is geometrically chiral when it lacks any mirror plane, space inversion center or roto-inversion axis [3]. Typically, the geometrical chirality is predefined by a material's chiral lattice structure, which is fixed upon the formation of the crystal. By contrast, a particularly unconventional scenario is the gyrotropic order [4][5][6][7][8], where chirality spontaneously emerges across a phase transition as the electron system breaks the relevant symmetries of an originally achiral lattice. Such a gyrotropic order, proposed as the quantum analogue of the cholesteric liquid crystals, has attracted significant interest [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. However, to date, a clear observation and manipulation of the gyrotropic order remain challenging. We report the realization of optical chiral induction and the observation of a gyrotropically ordered phase in the transition-metal dichalcogenide semimetal 1T -TiSe 2 . We show that shining mid-infrared circularly polarized light near the critical temperature leads to the preferential formation of one chiral domain. As a result, we are able to observe an out-of-plane circular photogalvanic current, whose direction depends on the optical induction. Our study provides compelling evidence for the spontaneous emergence of chirality in the correlated semimetal TiSe 2 [18]. Such chiral induction provides a new way of optical control over novel orders in quantum materials.In the presence of strong correlations, the behavior of electrons in a metal can signficantly deviate from a weakly-interacting Fermi gas, forming a wide range of complex, broken symmetry phases [19]. Recent theoretical works have highlighted their analogy with classical liquids [19], where a rich set of liquid crystalline phases that exhibit varying degrees of symmetry breaking and transport properties have been observed. A well-studied case is the nematic order [19][20][21], i.e., the spontaneous emergence of rotational anisotropy. In classical liquids, this is known as the nematic liquid crystal, whereas in quantum materials, it has recently been observed in quantum Hall systems, ruthenates, high temperature supercon-3 ductors [19], heavy-fermion superconductors [20], and correlated metallic pyrochlores [21].Another fascinating case is the gyrotropic order, i.e., the spontaneous emergence of geometrical chirality. In classical liquids, this is known as the cholesteric liquid crystal. In quantum materials, despite fundamental interest [4][5][6][7][8][9][10][11][12][13][14][15][16], a clear ...

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“…Second-order nonlinear optical responses are powerful tools in basic research, as probes of symmetry breaking [1][2][3][4][5], and in optical technology as the basis for generating currents from far-infrared [6] to X-ray wavelengths [7]. The recent surge of interest in Weyl semimetals with acentric crystal structures has led to the discovery of a host of σ (2) -related phenomena in this class of materials, such as polarization-selective conversion of light to dc current (photogalvanic effects) [8][9][10][11] and the observation of giant second-harmonic generation (SHG) efficiency in TaAs at photon energy 1.5 eV [12,13]. Here, we present measurements of the SHG spectrum of TaAs revealing that the response at 1.5 eV corresponds to the high-energy tail of a resonance at 0.7 eV, at which point the second harmonic conductivity is approximately 200 times larger than seen in the standard candle nonlinear crystal, GaAs.…”

mentioning

confidence: 99%

Resonance-enhanced optical nonlinearity in the Weyl semimetal TaAs

et al. 2018

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The dash-dotted curve in Figure 3b is a fit to |σ shg zzz | based on the two-photon term in equation (3). Given the simplicity of the model relative to the complexity of the full 3D bandstructure of TaAs, the 3D version of the RM model describes the data remarkably well. The peak position, low, and high energy tails of the spectrum are best described using parameterst = 1.5,δ = 1.4,t AB = 0.02, and ∆ = 0.428. The lattice parameters for TaAs are c = 1.165 nm, and b = a = 0.344 nm.The theory discussed above helps to identify the factors that contribute to a large SHG response. The first is a polar crystal structure such as 4mm (TaAs, NbAs, etc.) or mm2 (single layer monochalcogenides) consistent with a phenomenological description in terms of coupled ferroelectric chains. However, even when this description is possible there is a global bound on the frequency integrated second-order response, Σ shift z , of a system described by H RM that is given by,where G is also a dimensionless function of the dimensionless parameters, with a global maximum 0.604 [17]. Given this bound on Σ shift z , it is clear that the single most important factor in optimizing the second-order response of a 3D crystal is the effective aspect ratio parameter c 2 /ab.We conclude by addressing the question of ultimate bounds on Σ shift z , which is relevant not only to SHG, but to sensitivity of photodetectors and efficiency of solar cells based on Berry curvature generated intrinsic photogalvanic effects [21,28] as well. We have discovered a new connection between Σ shift z and the modern theory of polarization that generalizes the formulae for spectral weight beyond the RM Hamiltonian. Specifically we show that Σ shift z is unbounded and potentially divergent when the possibility of next-neighbor hopping is included.As demonstrated in the Supplementary Information, Σ shift z in two band systems, regardless of dimensionality d and range of electron hopping amplitude is given by,

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Spatially dispersive circular photogalvanic effect in a Weyl semimetal

Cited by 135 publications

References 46 publications

Anisotropic ultrasensitive PdTe ₂ -based phototransistor for room-temperature long-wavelength detection

Anisotropic ultrasensitive PdTe ₂ -based phototransistor for room-temperature long-wavelength detection

Spontaneous gyrotropic electronic order in a transition-metal dichalcogenide

Resonance-enhanced optical nonlinearity in the Weyl semimetal TaAs

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Spatially dispersive circular photogalvanic effect in a Weyl semimetal

Cited by 135 publications

References 46 publications

Anisotropic ultrasensitive PdTe 2 -based phototransistor for room-temperature long-wavelength detection

Anisotropic ultrasensitive PdTe 2 -based phototransistor for room-temperature long-wavelength detection

Spontaneous gyrotropic electronic order in a transition-metal dichalcogenide

Resonance-enhanced optical nonlinearity in the Weyl semimetal TaAs

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Anisotropic ultrasensitive PdTe ₂ -based phototransistor for room-temperature long-wavelength detection

Anisotropic ultrasensitive PdTe ₂ -based phototransistor for room-temperature long-wavelength detection