ARPES study of LSCO and PBCO: Electronic structure of the stripe phase and the 1/4-filled Cu-O chains

We have studied the electronic structure of the stripe phase in La 2-x Sr x CuO 4 (LSCO) and the Cu-O chains in PrBa 2 Cu 3 O 7 (Pr123) and PrBa 2 Cu 4 O 8 (Pr124) using angle-resolved photoemission spectroscopy (ARPES). In LSCO with x=0.12, the spectral feature near the Fermi level (EF) is almost flat from (π, 0) to (π, π/4), namely, along the stripe direction in LSCO. While the 1/4-filled chain in Pr123 has a band gap because of charge ordering, the metallic chain in Pr124 shows a dispersive feature which reaches EF at ~(π, π/4) and a flat feature near EF which is similar to that observed in the stripe phase of LSCO. Although Pr124 shows spectral-weight suppression near EF due to the instability toward charge ordering, the suppression is imperfect and Pr124 has a substantial spectral weight at EF probably due to the chain-chain coupling. This is in sharp contrast to LSCO with the perfect gap opening near (π, π/4). The difference between the stripe phase in LSCO and the coupled chains of Pr124 would be derived from the interaction between the stripe and the neighboring Cu spins which suppresses the charge ordering along the stripe.

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The electronic structure of epitaxial graphene—A view from angle-resolved photoemission spectroscopy

10.1093/oxfordhb/9780199533046.013.14 ◽

2017 ◽

Author(s):

S.Y. Zhou ◽

A. Lanzara

Keyword(s):

Electronic Structure ◽

Quantum Confinement ◽

Single Layer ◽

Epitaxial Graphene ◽

Photoemission Spectroscopy ◽

Angle Resolved Photoemission Spectroscopy ◽

Substrate Interaction ◽

Conduction Bands ◽

Gap Opening

This article analyzes the electronic structure of epitaxial graphene using angle-resolved photoemission spectroscopy (ARPES). It first describes how the carbon atoms in graphene are arranged before discussing the growth and characterization of graphene samples. It then considers the electronic structure of epitaxial graphene, along with the gap opening in single-layer epitaxial graphene. It also examines possible mechanisms for the gap opening in graphene, including quantum confinement, mixing of the states between the Brillouin zone corner K points induced by scattering, and hybridization of the valence and conduction bands caused by symmetry breaking in carbon sublattices. Clear deviations from the conical dispersions are observed near the Diracpoint energy, which can be interpreted as a gap opening attributed to graphene–substrate interaction. Graphene–substrate interaction is thus a promising route for engineering the bandgap in graphene.

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Electronic structure and signature of Tomonaga–Luttinger liquid state in epitaxial CoSb1−x nanoribbons

npj Quantum Materials ◽

10.1038/s41535-021-00381-y ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Rui Lou ◽

Minyinan Lei ◽

Wenjun Ding ◽

Wentao Yang ◽

Xiaoyang Chen ◽

...

Keyword(s):

Electronic Structure ◽

Luttinger Liquid ◽

Spectral Weight ◽

Photoemission Spectroscopy ◽

Strong Correlations ◽

Fermi Surfaces ◽

Angle Resolved Photoemission Spectroscopy ◽

Temperature Scaling ◽

Interfacial Charge

AbstractRecently, monolayer CoSb/SrTiO3 has been proposed as a candidate harboring interfacial superconductivity in analogy with monolayer FeSe/SrTiO3. Experimentally, while the CoSb-based compounds manifesting as nanowires and thin films have been realized on SrTiO3 substrates, serving as a rich playground, their electronic structures are still unknown and yet to be resolved. Here, we have fabricated CoSb1−x nanoribbons with quasi-one-dimensional stripes on SrTiO3(001) substrates using molecular beam epitaxy and investigated the electronic structure by in situ angle-resolved photoemission spectroscopy. Straight Fermi surfaces without lateral dispersions are observed. CoSb1−x/SrTiO3 is slightly hole doped, where the interfacial charge transfer is opposite to that in monolayer FeSe/SrTiO3. The spectral weight near the Fermi level exhibits power-law-like suppression and obeys a universal temperature scaling, serving as the signature of Tomonaga–Luttinger liquid (TLL) state. The obtained TLL parameter of ~0.21 shows the underlying strong correlations. Our results not only suggest CoSb1−x nanoribbon as a representative TLL system but also provide clues for further investigations on the CoSb-related interface.

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