2017
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J.-M. Poumirol; P. Q. Liu; T. M. Slipchenko; A. Y. Nikitin; L. Martin-Moreno; J. Faist; A. B. Kuzmenko Electrically controlled terahertz magneto-optical phenomena in continuous and patterned graphene Journal Article In: Nature Communications, 8 (14626), 2017. Abstract | Links | BibTeX @article{Poumirol2017,
title = {Electrically controlled terahertz magneto-optical phenomena in continuous and patterned graphene},
author = {J.-M. Poumirol and P. Q. Liu and T. M. Slipchenko and A. Y. Nikitin and L. Martin-Moreno and J. Faist and A. B. Kuzmenko},
editor = {Nature},
url = {http://www.nature.com/articles/ncomms14626},
doi = {10.1038/ncomms14626},
year = {2017},
date = {2017-01-18},
journal = {Nature Communications},
volume = {8},
number = {14626},
abstract = {The magnetic circular dichroism and the Faraday rotation are the fundamental phenomena of great practical importance arising from the breaking of the time reversal symmetry by a magnetic field. In most materials, the strength and the sign of these effects can be only controlled by the field value and its orientation. Furthermore, the terahertz range is lacking materials having the ability to affect the polarization state of the light in a non-reciprocal manner. Here we demonstrate, using broadband terahertz magneto-electro-optical spectroscopy, that in graphene both the magnetic circular dichroism and the Faraday rotation can be modulated in intensity, tuned in frequency and, importantly, inverted using only electrostatic doping at a fixed magnetic field. In addition, we observe strong magneto-plasmonic resonances in a patterned array of graphene antidots, which potentially allows exploiting these magneto-optical phenomena in a broad THz range.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The magnetic circular dichroism and the Faraday rotation are the fundamental phenomena of great practical importance arising from the breaking of the time reversal symmetry by a magnetic field. In most materials, the strength and the sign of these effects can be only controlled by the field value and its orientation. Furthermore, the terahertz range is lacking materials having the ability to affect the polarization state of the light in a non-reciprocal manner. Here we demonstrate, using broadband terahertz magneto-electro-optical spectroscopy, that in graphene both the magnetic circular dichroism and the Faraday rotation can be modulated in intensity, tuned in frequency and, importantly, inverted using only electrostatic doping at a fixed magnetic field. In addition, we observe strong magneto-plasmonic resonances in a patterned array of graphene antidots, which potentially allows exploiting these magneto-optical phenomena in a broad THz range. |
I. Crassee; F. Borondics; M. K. Tran; G. Autès; A. Magrez; P. Bugnon; H. Berger; J. Teyssier; O. V. Yazyev; M. Orlita; A. Akrap BiTeCl and BiTeBr: A comparative high-pressure optical study Journal Article In: Physical Review B, 95 , pp. 045201, 2017. Abstract | Links | BibTeX @article{Crassee2017,
title = {BiTeCl and BiTeBr: A comparative high-pressure optical study},
author = {I. Crassee and F. Borondics and M. K. Tran and G. Autès and A. Magrez and P. Bugnon and H. Berger and J. Teyssier and O. V. Yazyev and M. Orlita and A. Akrap},
editor = {APS},
url = {http://journals.aps.org/prb/abstract/10.1103/PhysRevB.95.045201},
doi = {10.1103/PhysRevB.95.045201},
year = {2017},
date = {2017-01-10},
journal = {Physical Review B},
volume = {95},
pages = {045201},
abstract = {We here report a detailed high-pressure infrared transmission study of BiTeCl and BiTeBr. We follow the evolution of two band transitions: the optical excitation β between two Rashba-split conduction bands, and the absorption γ across the band gap. In the low-pressure range, p<4 GPa, for both compounds β is approximately constant with pressure and γ decreases, in agreement with band structure calculations. In BiTeCl, a clear pressure-induced phase transition at 6 GPa leads to a different ground state. For BiTeBr, the pressure evolution is more subtle, and we discuss the possibility of closing and reopening of the band gap. Our data is consistent with a potential Weyl phase in BiTeBr at 5–6 GPa, followed by the onset of a structural phase transition above 7 GPa.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We here report a detailed high-pressure infrared transmission study of BiTeCl and BiTeBr. We follow the evolution of two band transitions: the optical excitation β between two Rashba-split conduction bands, and the absorption γ across the band gap. In the low-pressure range, p<4 GPa, for both compounds β is approximately constant with pressure and γ decreases, in agreement with band structure calculations. In BiTeCl, a clear pressure-induced phase transition at 6 GPa leads to a different ground state. For BiTeBr, the pressure evolution is more subtle, and we discuss the possibility of closing and reopening of the band gap. Our data is consistent with a potential Weyl phase in BiTeBr at 5–6 GPa, followed by the onset of a structural phase transition above 7 GPa. |
2016
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A. Akrap; M. Hakl; S. Tchoumakov; I. Crassee; J. Kuba; M. O. Goerbig; C. C. Homes; O. Caha; J. Novák; F. Teppe; W. Desrat; S. Koohpayeh; L. Wu; N. P. Armitage; A. Nateprov; E. Arushanov; Q. D. Gibson; R. J. Cava; D. van der Marel; B. A. Piot; C. Faugeras; G. Martinez; M. Potemski; M. Orlita Magneto-Optical Signature of Massless Kane Electrons in Cd3As2 Journal Article In: Physical Review Letters, 117 , pp. 136401, 2016. Abstract | Links | BibTeX @article{Akrap2016,
title = {Magneto-Optical Signature of Massless Kane Electrons in Cd3As2},
author = {A. Akrap and M. Hakl and S. Tchoumakov and I. Crassee and J. Kuba and M. O. Goerbig and C. C. Homes and O. Caha and J. Novák and F. Teppe and W. Desrat and S. Koohpayeh and L. Wu and N. P. Armitage and A. Nateprov and E. Arushanov and Q. D. Gibson and R. J. Cava and D. van der Marel and B. A. Piot and C. Faugeras and G. Martinez and M. Potemski and M. Orlita},
editor = {APS},
url = {http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.136401},
doi = {10.1103/PhysRevLett.117.136401},
year = {2016},
date = {2016-09-21},
journal = {Physical Review Letters},
volume = {117},
pages = {136401},
abstract = {We report on optical reflectivity experiments performed on Cd3As2 over a broad range of photon energies and magnetic fields. The observed response clearly indicates the presence of 3D massless charge carriers. The specific cyclotron resonance absorption in the quantum limit implies that we are probing massless Kane electrons rather than symmetry-protected 3D Dirac particles. The latter may appear at a smaller energy scale and are not directly observed in our infrared experiments.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report on optical reflectivity experiments performed on Cd3As2 over a broad range of photon energies and magnetic fields. The observed response clearly indicates the presence of 3D massless charge carriers. The specific cyclotron resonance absorption in the quantum limit implies that we are probing massless Kane electrons rather than symmetry-protected 3D Dirac particles. The latter may appear at a smaller energy scale and are not directly observed in our infrared experiments. |
Pieter J. de Visser; Julien Levallois; Michaël K. Tran; Jean-Marie Poumirol; Ievgeniia O. Nedoliuk; Jérémie Teyssier; Ctirad Uher; Dirk van der Marel; Alexey B. Kuzmenko Suppressed Magnetic Circular Dichroism and Valley-Selective Magnetoabsorption due to the Effective Mass Anisotropy in Bismuth Journal Article In: Physical Review Letters, 117 (017402), 2016. Abstract | Links | BibTeX @article{deVisser2016,
title = {Suppressed Magnetic Circular Dichroism and Valley-Selective Magnetoabsorption due to the Effective Mass Anisotropy in Bismuth},
author = {Pieter J. de Visser and Julien Levallois and Michaël K. Tran and Jean-Marie Poumirol and Ievgeniia O. Nedoliuk and Jérémie Teyssier and Ctirad Uher and Dirk van der Marel and Alexey B. Kuzmenko},
editor = {APS},
url = {http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.017402},
doi = {http://dx.doi.org/10.1103/PhysRevLett.117.017402},
year = {2016},
date = {2016-06-29},
journal = {Physical Review Letters},
volume = {117},
number = {017402},
abstract = {We measure the far-infrared reflectivity and Kerr angle spectra on a high-quality crystal of pure semimetallic bismuth as a function of magnetic field, from which we extract the conductivity for left- and right-handed circular polarizations. The high spectral resolution allows us to separate the intraband Landau level transitions for electrons and holes. The hole transition exhibits 100% magnetic circular dichroism; it appears only for one polarization as expected for a circular cyclotron orbit. However, the dichroism for electron transitions is reduced to only 13±1%, which is quantitatively explained by the large effective mass anisotropy of the electron pockets of the Fermi surface. This observation is a signature of the mismatch between the metric experienced by the photons and the electrons. It allows for a contactless measurement of the effective mass anisotropy and provides a direction towards valley polarized magnetooptical pumping with elliptically polarized light.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We measure the far-infrared reflectivity and Kerr angle spectra on a high-quality crystal of pure semimetallic bismuth as a function of magnetic field, from which we extract the conductivity for left- and right-handed circular polarizations. The high spectral resolution allows us to separate the intraband Landau level transitions for electrons and holes. The hole transition exhibits 100% magnetic circular dichroism; it appears only for one polarization as expected for a circular cyclotron orbit. However, the dichroism for electron transitions is reduced to only 13±1%, which is quantitatively explained by the large effective mass anisotropy of the electron pockets of the Fermi surface. This observation is a signature of the mismatch between the metric experienced by the photons and the electrons. It allows for a contactless measurement of the effective mass anisotropy and provides a direction towards valley polarized magnetooptical pumping with elliptically polarized light. |
M. Tamagnone; C. Moldovan; J.-M. Poumirol; A. B. Kuzmenko; A. M. Ionescu and J. R. Mosig; J. Perruisseau-Carrier Near optimal graphene terahertz non-reciprocal isolator Journal Article In: Nature Communications, 7 (11216), 2016. Abstract | Links | BibTeX @article{Tamagnone2016,
title = {Near optimal graphene terahertz non-reciprocal isolator},
author = {M. Tamagnone and C. Moldovan and J.-M. Poumirol and A. B. Kuzmenko and A. M. Ionescu and J. R. Mosig and J. Perruisseau-Carrier},
editor = {Nature},
url = {http://www.nature.com/ncomms/2016/160406/ncomms11216/abs/ncomms11216.html},
doi = {10.1038/ncomms11216},
year = {2016},
date = {2016-04-06},
journal = {Nature Communications},
volume = {7},
number = {11216},
abstract = {Isolators, or optical diodes, are devices enabling unidirectional light propagation by using non-reciprocal optical materials, namely materials able to break Lorentz reciprocity. The realization of isolators at terahertz frequencies is a very important open challenge made difficult by the intrinsically lossy propagation of terahertz radiation in current non-reciprocal materials. Here we report the design, fabrication and measurement of a terahertz non-reciprocal isolator for circularly polarized waves based on magnetostatically biased monolayer graphene, operating in reflection. The device exploits the non-reciprocal optical conductivity of graphene and, in spite of its simple design, it exhibits almost 20 dB of isolation and only 7.5 dB of insertion loss at 2.9 THz. Operation with linearly polarized light can be achieved using quarter-wave plates as polarization converters. These results demonstrate the superiority of graphene with respect to currently used terahertz non-reciprocal materials and pave the way to a novel class of optimal non-reciprocal devices.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Isolators, or optical diodes, are devices enabling unidirectional light propagation by using non-reciprocal optical materials, namely materials able to break Lorentz reciprocity. The realization of isolators at terahertz frequencies is a very important open challenge made difficult by the intrinsically lossy propagation of terahertz radiation in current non-reciprocal materials. Here we report the design, fabrication and measurement of a terahertz non-reciprocal isolator for circularly polarized waves based on magnetostatically biased monolayer graphene, operating in reflection. The device exploits the non-reciprocal optical conductivity of graphene and, in spite of its simple design, it exhibits almost 20 dB of isolation and only 7.5 dB of insertion loss at 2.9 THz. Operation with linearly polarized light can be achieved using quarter-wave plates as polarization converters. These results demonstrate the superiority of graphene with respect to currently used terahertz non-reciprocal materials and pave the way to a novel class of optimal non-reciprocal devices. |