02182nas a2200301 4500008004500000020001400045245011000059210006900169260000800238300000600246490000800252520133400260653002201594653001201616100001801628700001201646700001701658700001401675700001801689700001701707700001901724700002001743700002101763700001401784700001901798700001401817856004901831 2020 Engldsh a2469-995000aLinear dichroism infrared resonance in overdoped, underdoped, and optimally doped cuprate superconductors0 aLinear dichroism infrared resonance in overdoped underdoped and cAug a60 v1023 a
By measuring the polarization changes in terahertz, infrared, and visible radiation over an extended energy range (3-2330 meV), we observe symmetry breaking in cuprate high-temperature superconductors over wide energy, doping, and temperature ranges. We measure the polarization rotation (Re[theta(F)]) and ellipticity (Im[theta(F)]) of transmitted radiation through thin films as the sample is rotated. We observe a twofold rotational symmetry in theta(F), which is associated with linear dichroism (LD) and occurs when electromagnetic radiation polarized along one direction is absorbed more strongly than radiation polarized in the perpendicular direction. Such polarization anisotropies can be generally associated with symmetry breakings. We measure the amplitude of the LD signal and study its temperature, energy, and doping dependence. The LD signal shows a resonant behavior with a peak in the few hundred meV range, which is coincident with the midinfrared optical feature that has been associated with the formation of the pseudogap state. The strongest LD signal is found in underdoped films, although it is also observed in optimally and overdoped samples. The LD signal is consistent with an electronic nematic order which is decoupled from the crystallographic axes as well as novel magnetoelectric effects.
10aMaterials Science10aPhysics1 aMukherjee, A.1 aSeo, J.1 aArik, M., M.1 aZhang, H.1 aZhang, C., C.1 aKirzhner, T.1 aGeorge, D., K.1 aMarkelz, A., G.1 aArmitage, N., P.1 aKoren, G.1 aWei, J., Y. T.1 aCerne, J. uhttps://markelz.physics.buffalo.edu/node/23800733nas a2200217 4500008004100000245011300041210006900154260003400223100001800257700001800275700001900293700002100312700001900333700002300352700002000375700001700395700002000412700002000432700001400452856004900466 2012 eng d00aMulti-component response in multilayer graphene revealed through terahertz and infrared magneto-spectroscopy0 aMulticomponent response in multilayer graphene revealed through aWollongong, Australiac9/20121 aEllis, C., T.1 aStier, A., V.1 aGeorge, D., K.1 aTischler, J., G.1 aGlaser, E., R.1 aMyers-Ward, R., L.1 aTedesco, J., L.1 aEddy, C., R.1 aGaskill, D., K.1 aMarkelz, A., G.1 aCerne, J. uhttps://markelz.physics.buffalo.edu/node/30701418nas a2200289 4500008004500000020001400045245011000059210006900169260000800238300000600246490000800252520061600260653001100876653001200887100002000899700001800919700001200937700001900949700001900968700001500987700001101002700001401013700002001027700001101047700002101058856004901079 2012 Engldsh a0031-900700aTerahertz Response and Colossal Kerr Rotation from the Surface States of the Topological Insulator Bi2Se30 aTerahertz Response and Colossal Kerr Rotation from the Surface S cFeb a50 v1083 aWe report the THz response of thin films of the topological insulator Bi2Se3. At low frequencies, transport is essentially thickness independent showing the dominant contribution of the surface electrons. Despite their extended exposure to ambient conditions, these surfaces exhibit robust properties including narrow, almost thickness-independent Drude peaks, and an unprecedentedly large polarization rotation of linearly polarized light reflected in an applied magnetic field. This Kerr rotation can be as large as 65 degrees and can be explained by a cyclotron resonance effect of the surface states.
10abi2te310aPhysics1 aAguilar, R., V.1 aStier, A., V.1 aLiu, W.1 aBilbro, L., S.1 aGeorge, D., K.1 aBansal, N.1 aWu, L.1 aCerne, J.1 aMarkelz, A., G.1 aOh, S.1 aArmitage, N., P. uhttps://markelz.physics.buffalo.edu/node/22100927nas a2200169 4500008004500000020002200045245009300067210006900160260001900229520038000248100001800628700001500646700002000661700001400681700001300695856004900708 2011 Engldsh a978-1-4577-0509-000aMagneto Optical Polarization Measurements using THz Polarization Modulation Spectroscopy0 aMagneto Optical Polarization Measurements using THz Polarization aNew YorkbIeee3 aWe report a new broad band technique for rapidly measuring the complex Faraday and Kerr rotations in materials such as topological insulators and graphene, combining the distinct advantages of THz time domain spectroscopy and polarization modulation techniques. The performance of the system is demonstrated using GaAs two dimensional electron gas in a magnetic field.
1 aStier, A., V.1 aGeorge, D.1 aMarkelz, A., G.1 aCerne, J.1 aKoch, M. uhttps://markelz.physics.buffalo.edu/node/24401840nas a2200313 4500008004500000020001400045245009000059210006900149260000800218300000600226490000700232520100400239653001501243653001201258653001701270653000801287653001301295653002801308653001001336653001201346653002401358653001701382653001001399100001701409700001701426700001401443700002001457856004901477 2005 Engldsh a1539-375500aLarge oxidation dependence observed in terahertz dielectric response for cytochrome c0 aLarge oxidation dependence observed in terahertz dielectric resp cOct a40 v723 aFar infrared dielectric response is used to characterize the collective mode density of states for cytochrome c as a function of oxidation state and hydration using terahertz time domain spectroscopy. A strong absorbance and refractive index increase was observed with the oxidation. A simple phenomenological fitting using a continuous distribution of oscillators reproduces the frequency dependence of the complex dielectric response as well as demonstrates quantitative agreement with a uniform increase in either mode density or polarizability with oxidation in the 5-80 cm(-1) frequency range. Hydration dependence measurements find that a difference in the equilibrium water content for ferri and ferro cytochrome c is not sufficient to account for the large change in terahertz response. The large dielectric increase at terahertz frequencies with oxidation suggests either a significant global softening of the potential and/or a significant increase in polarizability with oxidation.
10aabsorption10abinding10aconformation10adna10adynamics10aheart ferricytochrome-c10amodes10aPhysics10aprotein flexibility10aspectroscopy10astate1 aChen, J., Y.1 aKnab, J., R.1 aCerne, J.1 aMarkelz, A., G. uhttps://markelz.physics.buffalo.edu/node/26301843nas a2200193 4500008004100000245010000041210006900141260001900210300001900229490000800248520123500256100001601491700001701507700001401524700002401538700001801562700002001580856004901600 2004 eng d00aTerahertz measurements of the Photoactive Protein Bacteriorhodopsin mutant D96N: M and P states0 aTerahertz measurements of the Photoactive Protein Bacteriorhodop aWarrendale, PA apages261–2670 v8263 aWe use terahertz (THz) spectroscopy as a biomaterials characterization tool. Previously we have shown a strong contrast between the THz dielectric response for wild type (WT) and D96N mutant of bacteriorhodopsin. In those studies we observed a large increase in the THz absorbance of WT with excitation to thermally captured photo-intermediates whereas no such increase in absorbance was observed for the mutant D96N. These results suggest that the THz response is sensitive to structural changes and relative flexibility of biomolecules. However the photo-intermediate populations of the WT and D96N samples were not equivalent in those measurements. While the WT samples had relaxed (bR), M and P state intermediates present, the D96N samples had only bR and M states. Here we present terahertz absorbance measurements of D96N as a function of M and P state populations at room temperature. The THz response is constant for intermediate states populations up to 23% M state and up to 30% P state. These results verify that there is a fundamental difference in the conformational dynamics as measured by THz dielectric response for a single residue mutation.
We use photoluminescence to study the time-average energy distribution of electrons in the presence of strong steady-state drive at terahertz (THz) frequencies, in a modulation-doped 125 Angstrom AlGaAs/GaAs square well that is held at low lattice temperature TL. We find that the energy distribution can be characterized by an effective electron temperature, T-e(>T-L), that agrees well with values estimated from the THz-illuminated, dc conductivity. This agreement indicates that under strong THz drive, LO phonon scattering dominates both energy and momentum relaxation; that the carrier distribution maintains a heated, thermal form; and that phonon drift effects are negligible. (C) 1996 American Institute of Physics.
10ahot-electrons10aPhysics1 aAsmar, N., G.1 aCerne, J.1 aMarkelz, A., G.1 aGwinn, E., G.1 aSherwin, M., S.1 aCampman, K., L.1 aGossard, A., C. uhttps://markelz.physics.buffalo.edu/node/25800682nas a2200217 4500008004100000020001400041245011500055210006900170260001100239300001400250490000700264100001400271700002000285700002000305700001800325700001700343700002000360700001900380700001600399856004900415 1995 eng d a0163-182900aQUENCHING OF EXCITONIC QUANTUM-WELL PHOTOLUMINESCENCE BY INTENSE FAR-INFRARED RADIATION - FREE-CARRIER HEATING0 aQUENCHING OF EXCITONIC QUANTUMWELL PHOTOLUMINESCENCE BY INTENSE cFeb 15 a5253-52620 v511 aCerne, J.1 aMarkelz, A., G.1 aSherwin, M., S.1 aAllen, S., J.1 aSundaram, M.1 aGossard, A., C.1 aVanson, P., C.1 aBimberg, D. uhttps://markelz.physics.buffalo.edu/node/26200655nas a2200217 4500008004100000020001400041245008000055210006900135260001100204300001600215490000700231100001800238700002000256700001800276700001400294700002000308700002000328700002000348700002000368856004900388 1995 eng d a0163-182900aRESONANT-ENERGY RELAXATION OF TERAHERTZ-DRIVEN 2-DIMENSIONAL ELECTRON GASES0 aRESONANTENERGY RELAXATION OF TERAHERTZDRIVEN 2DIMENSIONAL ELECTR cJun 15 a18041-180440 v511 aAsmar, N., G.1 aMarkelz, A., G.1 aGwinn, E., G.1 aCerne, J.1 aSherwin, M., S.1 aCampman, K., L.1 aHopkins, P., F.1 aGossard, A., C. uhttps://markelz.physics.buffalo.edu/node/25900528nas a2200157 4500008004100000245010600041210006900147260001200216300001400228100001800242700001400260700001800274700001300292700001600305856004900321 1994 eng d00aFrequency Dependence of the Third Order Susceptibility of InAs Quantum Wells at Terahertz Frequencies0 aFrequency Dependence of the Third Order Susceptibility of InAs Q c08/1994 a1193-11961 aMarkelz, A.G.1 aCerne, J.1 aGwinn, E., G.1 aBrar, B.1 aKroemer, H. uhttps://markelz.physics.buffalo.edu/node/318