Ultrafast terahertz Faraday rotation in graphene

Heyman, James; Kune, R. F. Foo; Alebachew, B. A.; Nguyen, Minh D.; Robinson, Jeremy T.

doi:10.1063/1.4903212

Cited by 8 publications

(7 citation statements)

References 30 publications

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“…However, making electrical contacts that transfer a picosecond (ps) short signal without substantial distortions and broadening is rather challenging [1]. An elegant solution for the problem of ultrafast conductivity measurements can be found by using freely propagating terahertz (THz) waves.To date, THz spectroscopy has been used to study magnetotransport in a large diversity of materials [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. However, only a few of these studies have been dedicated to magnetically ordered materials and in none of these materials the magnetization could be reversed ultrafast.…”

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confidence: 99%

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Sub-100-ps dynamics of the anomalous Hall effect at terahertz frequencies

Huisman¹,

Mikhaylovskiy²,

Rasing³

et al. 2017

Phys. Rev. B

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We report about the anomalous Hall effect in 4f 3d metallic alloys measured using terahertz time-domain spectroscopy. The strength of the observed terahertz spin-dependent transport phenomenon is in good agreement with expectations based on electronic transport measurements. Employing this effect, we succeeded to reveal ultrafast dynamics of the anomalous Hall effect which accompanies the sub-100 picosecond optically induced magnetization reversal in a GdFeCo alloy. The experiments demonstrate the ability to control currents at terahertz frequencies in spintronic devices magnetically and ultrafast.To develop ultrafast spintronics logic protocols for high-speed data processing, one has to find a way to control and detect the spin-dependent transport ultrafast. The conventional approach to study magnetotransport is based on the application of an electrical voltage to a sample and the detection of the subsequent electrical current via electrodes. However, making electrical contacts that transfer a picosecond (ps) short signal without substantial distortions and broadening is rather challenging [1]. An elegant solution for the problem of ultrafast conductivity measurements can be found by using freely propagating terahertz (THz) waves.To date, THz spectroscopy has been used to study magnetotransport in a large diversity of materials [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. However, only a few of these studies have been dedicated to magnetically ordered materials and in none of these materials the magnetization could be reversed ultrafast. To reveal sub-100 ps dynamics in the anomalous Hall effect, we have chosen ferrimagnetic Gdx(FeCo)1-x thin films, as they are expected to show a significant anomalous Hall effect [18][19][20], and are known for their ultrafast all-optical magnetization reversal [21][22][23][24][25][26].The studied Gdx(Fe0.875Co0.125)1-x samples are 20 nm thick amorphous films, which have adjacent 5 nm SiN protecting layers and are deposited using magnetron sputtering. These samples have a ferrimagnetic ordering and an out-of-plane magnetic anisotropy in the studied Gd concentration range (0.2

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confidence: 99%

“…To date, THz spectroscopy has been used to study magnetotransport in a large diversity of materials [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. However, only a few of these studies have been dedicated to magnetically ordered materials and in none of these materials the magnetization could be reversed ultrafast.…”

mentioning

confidence: 99%

Sub-100-ps dynamics of the anomalous Hall effect at terahertz frequencies

Huisman¹,

Mikhaylovskiy²,

Rasing³

et al. 2017

Phys. Rev. B

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“…Secondly, there are several interesting works devoted to the study of properties of the graphene under the MF. An article by Heyman et al [21] is devoted to an experimental research of a SLG in a sapphire substrate. In this paper, data on the conductivity and the carrier scattering rate of the SLG are described in detail.…”

Section: Introductionmentioning

confidence: 99%

Polarization properties of few-layer graphene on silicon substrate in terahertz frequency range

et al. 2019

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Terahertz time-domain spectroscopic polarimetry (THz-TDSP) method was used to study polarization properties of a few-layer graphene (FLG) on a silicon (Si) substrate in terahertz (THz) frequency range under an external optical pumping and an external static magnetic field. Frequency dependencies of azimuth and ellipticity angles of a polarization ellipse and the polarization ellipse at various frequencies of the electromagnetic waves transmitted through the Si substrate and the FLG on the Si substrate were obtained experimentally and theoretically. The results confirm the fact that, based on the FLG, it is possible to devise efficient tunable THz polarization modulators for use in the latest security and telecommunication systems.

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“…By contrast, the THz Hall effect is more conceptually identical to the DC Hall effect. Combining THz technology with the optical Hall effect, a method for THz optical-Hall measurements was presented 9 and used to measure the material parameters in a semiconductor 10 and graphene 11 .…”

Section: Introductionmentioning

confidence: 99%

Cross-polarization coupling terahertz time-domain spectroscopy in a semiconductor based on the Hall effect

Liu

Wang

2017

Sci Rep

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We propose a new type of terahertz time-domain spectroscopy in an isotropic semiconductor wafer applied by a magnetic field in which two cross-polarization THz pulses couple with each other via the Hall effect. We built a classic theoretic model to describe cross-polarization coupling THz spectroscopy (CPCTS). Numerical simulations show that the magnetic field can clearly affect the spectral features of the two THz pulses via the Hall effect in which both the magnitude and direction of the magnetic field and the thickness of the wafer play important roles. Using CPCTS, we present an improved method that is non-contact to measure the material parameters, such as the damping constant and carrier density of a semiconductor wafer, and discuss the possibility of THz functional devices. Finally, we describe an experimental scheme to guide CPCTS.

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Ultrafast terahertz Faraday rotation in graphene

Cited by 8 publications

References 30 publications

Sub-100-ps dynamics of the anomalous Hall effect at terahertz frequencies

Sub-100-ps dynamics of the anomalous Hall effect at terahertz frequencies

Polarization properties of few-layer graphene on silicon substrate in terahertz frequency range

Cross-polarization coupling terahertz time-domain spectroscopy in a semiconductor based on the Hall effect

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