Circular Dichroism in Photoelectron Angular Distributions from Oriented Linear Molecules

Dubs, Richard L.; Dixit, S. N.; McKoy, Vincent

doi:10.1103/physrevlett.54.1249

Cited by 146 publications

(73 citation statements)

References 9 publications

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“…Before discussing the usefulness of the CD-ARPES technique, we discuss the origin of the CD-ARPES signal as there are different views on the origin of the CD signal 32,[38][39][40] . CD signal refers to the difference in the reaction to right and left circularly polarized light.…”

Section: Chiral Oam Structurementioning

confidence: 99%

dxz/yz orbital subband structures and chiral orbital angular momentum in the (001) surface states of SrTiO3

et al. 2017

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We have performed angle resolved photoemission spectroscopy (ARPES) experiments on the surface states of SrTiO3(001) using linearly and circularly polarized light to investigate the subband structures of out-of-plane d xz/yz orbitals and chiral orbital angular momentum (OAM). The data taken in the first Brillouin zone reveal new subbands for d xz/yz orbitals with Fermi wave vectors of 0.25 and 0.45Å −1 in addition to the previously reported ones. As a result, there are at least two subbands for all the Ti 3d t2g orbitals. Our circular dichroism ARPES data is suggestive of a chiral OAM structure in the surface states and may provide clues to the origin of the linear Rashba-like surface band splitting.

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Section: Chiral Oam Structurementioning

confidence: 99%

dxz/yz orbital subband structures and chiral orbital angular momentum in the (001) surface states of SrTiO3

et al. 2017

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“…Although case (b) is the one that interests us, we first describe case (a), as this is a large effect, and needs to be correctly accounted for in the analysis of the data [13][14][15] . In Fig.…”

mentioning

confidence: 99%

Spontaneous breaking of time-reversal symmetry in the pseudogap state of a high-Tc superconductor

Kaminski

Rosenkranz

Fretwell

et al. 2002

Nature

308

310

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When matter undergoes a phase transition from one state to another, usually a change in symmetry is observed, as some of the symmetries exhibited are said to be spontaneously broken. The superconducting phase transition in the underdoped high-T c superconductors is rather unusual, in that it is not a mean-field transition as other superconducting transitions are. Instead, it is observed that a pseudo-gap in the electronic excitation spectrum appears at temperatures T * higher than T c , while phase coherence, and superconductivity, are established at T c (Refs. 1, 2). One would then wish to understand if T * is just a crossover, controlled by fluctuations in order which will set in at the lower T c (Refs. 3, 4), or whether some symmetry is spontaneously broken at T * (Refs. 5-10). Here, using angle-resolved photoemission with circularly polarized light, we find that, in the pseudogap state, left-circularly polarized photons give a different photocurrent than right-circularly polarized 2 photons, and therefore the state below T * is rather unusual, in that it breaks time reversal symmetry 11 . This observation of a phase transition at T* provides the answer to a major mystery of the phase diagram of the cuprates. The appearance of the anomalies below T* must be related to the order parameter that sets in at this characteristic temperature .We have investigated the time reversal invariance of the electronic states by ARPES, which becomes sensitive to this symmetry by the use of circularly polarized photons 11 .The measured ARPES intensity I α ∝ |M α | 2 , where the matrix element M α = 〈p|O α |ψ(k)〉, describes the ejection of the electron from an initial state |ψ(k)〉 to a final state |p〉, and the dipole operator O α contains the vector potential of α = L (left) or α = R (right) circularly polarized photons. The experimental setup is shown in Fig. 1. It consists of a plane grating monochromator beamline at the Aladdin synchrotron as a source of linearly polarized photons, quadruple reflection polarizer 12 , refocusing mirror, and the experimental chamber.It is crucial in this experiment, which is essentially measuring absolute intensity changes, to minimize beam movement, as extraneous intensity changes can occur from such movements.We therefore monitor the beam position, as shown in Fig. 1, finding a small residual beam movement of 150 µm, which is compensated for by adjusting the experimental chamber position as the polarizer is rotated. In the experiment one wishes to maximize the product TP 2 , where T denotes the transmission and P the polarization. In our experiment, this is accomplished with P = 86%, as shown in Fig. 1d. Although case (b) is the one that interests us, we first describe case (a), as this is a large effect, and needs to be correctly accounted for in the analysis of the data 13-15 . In Fig. 2a we it was found experimentally 16 , and confirmed here, that it is a symmetry direction for the CuO 2 planar electronic states). This is seen in Fig. 2e, where we plot spectra obtained at point M 1 that i...

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“…Microscopically, it comes from variation of the linear CD signal with molecular orientation. [35][36][37] For instance, R…”

Section: A Signatures Of Chirality Exchange In the 2d Spectrum Of Thmentioning

confidence: 99%

Novel coherent two-dimensional optical spectroscopy probes of chirality exchange and fluctuations in molecules

Šanda

Mukamel

2011

The Journal of Chemical Physics

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We demonstrate how stochastic transitions between molecular configurations with opposite senses of chirality may be probed by 2D optical signals with specific pulse polarization configurations. The third-order optical response of molecular dimers (such as biphenyls) with dynamical axial chirality is calculated to order of k 2 in the wavevector of light. Spectroscopic signatures of equilibrium chirality fluctuations are predicted for three dynamical models (Ornstein-Uhlenbeck, two-state jump, and diffusion in double well) of the dihedral angle that controls the chirality.

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Circular Dichroism in Photoelectron Angular Distributions from Oriented Linear Molecules

Cited by 146 publications

References 9 publications

dxz/yz orbital subband structures and chiral orbital angular momentum in the (001) surface states of SrTiO3

dxz/yz orbital subband structures and chiral orbital angular momentum in the (001) surface states of SrTiO3

Spontaneous breaking of time-reversal symmetry in the pseudogap state of a high-Tc superconductor

Novel coherent two-dimensional optical spectroscopy probes of chirality exchange and fluctuations in molecules

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