Measurement of the infrared complex Faraday angle in semiconductors and insulators

Kim, Myoung-Hwan; Kurz, Volker; Acbas, G.; Ellis, Chase T.; Černe, J.

doi:10.1364/josab.28.000199

Cited by 16 publications

(9 citation statements)

References 23 publications

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“…In order to measure the rotation and ellipticity angles θ and ψ in a broad energy range we developed a sensitive experimental technique which is described in detail in [18]. We use a Xe lamp (0.33-2.7 eV) with a double prism CaF 2 monochromator and discrete spectral lines from CO 2 (115-133 meV) and CO (215-232 meV) lasers [33]. Measurements are done in the reflection geometry close to normal incidence (≈6…”

Section: Methodsmentioning

confidence: 99%

“…We use a Xe lamp (0.33-2.7 eV) with a double prism CaF 2 monochromator and discrete spectral lines from CO 2 (115-133 meV) and CO (215-232 meV) lasers. 30 Measurements are done in the reflection geometry close to normal incidence (≈ 6 • with respect to the sample normal) whereas we assume that the polarization plane rotation due to the longitudinal Kerr effect is negligible. The samples are mounted on a custom made rotating sample holder attached to the cold finger which is cooled down to 15 K. The holder enables a precise rotation of the sample, and thus of the magnetization with respect to the incident polarization using external magnetic field B, which is applied along a fixed in-plane direction.…”

Section: Methodsmentioning

confidence: 99%

“…31 The optical axis of the PEM is oriented 45 • with respect to the magnetic field axis and the detected signals at f and 2f are proportional to ellipticity (ψ) and rotation (θ) of the reflected light polarization, respectively. 30,31 In the first step of the measurement, the polarization of the incident light is set parallel with the magnetization orientation, so any non-zero signal detected at f or 2f is just background unrelated to magneto-optical properties of the sample. In the second step we apply B ≈ 0.6 T which rotates the magnetization to β = 45 • relative to the incident beam polarization.…”

Section: Methodsmentioning

confidence: 99%

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Systematic study of magnetic linear dichroism and birefringence in (Ga,Mn)As

et al. 2014

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Magnetic linear dichroism and birefringence in (Ga,Mn)As epitaxial layers is investigated by measuring the polarization plane rotation of reflected linearly polarized light when magnetization lies in the plane of the sample. We report on the spectral dependence of the rotation and ellipticity angles in a broad energy range of 0.12-2.7 eV for a series of optimized samples covering a wide range on Mn dopings and Curie temperatures and find a clear blueshift of the dominant peak at energy exceeding the host material band gap. These results are discussed within the framework of the k · p and mean-field kinetic-exchange model of the (Ga,Mn)As band structure. We infer that disorder-induced nondirect transitions significantly influence magneto-optical properties of (Ga,Mn)As.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Systematic study of magnetic linear dichroism and birefringence in (Ga,Mn)As

et al. 2014

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“…The MLD is measured using discrete spectral lines from CO 2 (115 -133 meV), CO (215 -232 meV) and Ti-sapphire (1.63 eV) lasers and two distinct broadband light sources: a halogen lamp with a diffraction grating monochromator (Jobin Yvon Spex Model HR250) and the Xe lamp (Perkin-Elmer Cermax) with a double-pass CaF 2 prism monochromator (Perkin-Elmer Model 99). 28 The main advantage of the prism monochromator is that each wavelength is dispersed into a unique angle, which is not the case for the diffraction grating monochromator where a cut-off filter is used to remove the higher order diffraction peaks. Unlike typical arc lamps, which are housed in glass (limiting their usage to below 2.5 µm), our Xe lamp is equipped with a sapphire window that enables access to longer wavelengths.…”

Section: Methodsmentioning

confidence: 99%

High precision magnetic linear dichroism measurements in (Ga,Mn)As

Tesařová

Šubrt

Malý

et al. 2012

Review of Scientific Instruments

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Investigation of magnetic materials using the first-order magneto-optical Kerr effects (MOKEs) is well established and is frequently used. On the other hand, the utilization of the second-order (or quadratic) magneto-optical (MO) effects for the material research is rather rare. This is due to the small magnitude of quadratic MO signals and the fact that the signals are even in magnetization (i.e., they do not change a sign when the magnetization orientation is reversed), which makes it difficult to separate second-order MO signals from various experimental artifacts. In 2005 a giant quadratic MO effect-magnetic linear dichroism (MLD)-was observed in the ferromagnetic semiconductor (Ga,Mn)As. This discovery not only provided a new experimental tool for the investigation of in-plane magnetization dynamics in (Ga,Mn)As using light at normal incidence, but it also motivated the development of experimental techniques for the measurement of second-order MO effects in general. In this paper we compare four different experimental techniques that can be used to measure MLD and to separate it from experimental artifacts. We show that the most reliable results are obtained when we monitor the polarization of reflected light while the magnetization of the sample is rotated by applying an external magnetic field. Using this technique we measure the MLD spectra of (Ga,Mn)As in a broad spectral range from 0.1 eV to 2.7 eV and we observe that MLD has a magnitude comparable to the polar MOKE signals in this material.

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“…This MIR light is directed onto the sample at near normal incidence, and the reflected beam polarization is analyzed using a combination of photoelastic modulation and lock-in techniques that allow for the simultaneous determination of the complex Kerr angle and the magneto-reflectivity35464748. The probing beam at the sample is on the order of hundreds of microns in diameter and therefore our measurements probe a mixture of response from all forms of graphene present in the laser spot.…”

Section: Methodsmentioning

confidence: 99%

Magneto-optical fingerprints of distinct graphene multilayers using the giant infrared Kerr effect

Ellis

Stier

Kim

et al. 2013

Sci Rep

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The remarkable electronic properties of graphene strongly depend on the thickness and geometry of graphene stacks. This wide range of electronic tunability is of fundamental interest and has many applications in newly proposed devices. Using the mid-infrared, magneto-optical Kerr effect, we detect and identify over 18 interband cyclotron resonances (CR) that are associated with ABA and ABC stacked multilayers as well as monolayers that coexist in graphene that is epitaxially grown on 4H-SiC. Moreover, the magnetic field and photon energy dependence of these features enable us to explore the band structure, electron-hole band asymmetries, and mechanisms that activate a CR response in the Kerr effect for various multilayers that coexist in a single sample. Surprisingly, we find that the magnitude of monolayer Kerr effect CRs is not temperature dependent. This unexpected result reveals new questions about the underlying physics that makes such an effect possible.T he discovery of a stable monolayer flake of graphene by Novoselov et al. 1 set off a massive investigation of the remarkable properties of mono-and multilayer graphene. The simple hexagonal carbon lattice of monolayer graphene results in a unique linear dispersion with low energy excitations that are massless and relativistic. From these characteristics arise fascinating properties such as square root magnetic field (B) dependence of the cyclotron resonance (CR) frequency, a lowest Landau level (LL) independent of B, anomalous chiral quantum Hall effects 2 , unusual magnetic field and Fermi energy dependence of the AC Hall conductivity 3 , and the presence of a finite longitudinal conductivity s xx without charge carriers 4 . Studies of multilayer graphene have proven equally interesting due to the existence of massive Dirac fermions, unique broken symmetry states 5 , and the existence of a readily tunable bandgap 6-8 . In addition, the electronic structure of multilayer graphene is highly dependent upon the stacking geometry and thickness of layers, yielding a wide range of electronic tunability for graphene systems 17,18,24 . To that end, both scientists and engineers alike have been fascinated by graphene and all of its possible applications, such as high frequency analog ballistic transistors 8-10 , surface enhanced spectroscopy 2-4 , photo-detectors 11 , transparent conductors 13 , and as proposed in this Report, ultra-fast optical modulators and tunable polarizers.When placed in an out-of-plane magnetic field, multilayer graphene's electronic bands condense into discrete energy states (LLs) that are especially sensitive to the coupling strength between layers. This coupling strength is dependent upon the relative orientation of layers and the total number of layers in a graphene stack. Graphene's strong dependence on interlayer coupling has been demonstrated many times for monolayer 5-7 (uncoupled) and bilayer 7-9 (coupled) graphene, which yield LL energies proportional to ffiffiffi B p and B, respectively. In this study we systematically investiga...

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Measurement of the infrared complex Faraday angle in semiconductors and insulators

Cited by 16 publications

References 23 publications

Systematic study of magnetic linear dichroism and birefringence in (Ga,Mn)As

Systematic study of magnetic linear dichroism and birefringence in (Ga,Mn)As

High precision magnetic linear dichroism measurements in (Ga,Mn)As

Magneto-optical fingerprints of distinct graphene multilayers using the giant infrared Kerr effect

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