scholarly journals Indirect to Direct Gap Crossover in Two-Dimensional InSe Revealed by Angle-Resolved Photoemission Spectroscopy

ACS Nano ◽  
2019 ◽  
Author(s):  
Matthew J. Hamer ◽  
Johanna Zultak ◽  
Anastasia V. Tyurnina ◽  
Viktor Zólyomi ◽  
Daniel Terry ◽  
...  
Keyword(s):  
Photoemission Spectroscopy ◽  
Two Dimensional ◽  
Angle Resolved Photoemission Spectroscopy

scholarly journals Discovery of Two Families of Vsb-Based Compounds with V-Kagome Lattice

2021 ◽  
Vol 38 (12) ◽  
pp. 127102
Author(s):  
Yuxin Yang ◽  
Wenhui Fan ◽  
Qinghua Zhang ◽  
Zhaoxu Chen ◽  
Xu Chen ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Theoretical Calculations ◽  
Photoemission Spectroscopy ◽  
Two Dimensional ◽  
Kagome Lattice ◽  
Space Group ◽  
Kagomé Lattice ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Nonmagnetic Metals

We report the structure and physical properties of two newly discovered compounds AV8Sb12 and AV6Sb6 (A = Cs, Rb), which have C 2 (space group: Cmmm) and C 3 (space group: R 3 ¯ m ) symmetry, respectively. The basic V-kagome unit appears in both compounds, but stacking differently. A V2Sb2 layer is sandwiched between two V3Sb5 layers in AV8Sb12, altering the V-kagome lattice and lowering the symmetry of kagome layer from hexagonal to orthorhombic. In AV6Sb6, the building block is a more complex slab made up of two half-V3Sb5 layers that are intercalated by Cs cations along the c-axis. Transport property measurements demonstrate that both compounds are nonmagnetic metals, with carrier concentrations at around 1021 cm−3. No superconductivity has been observed in CsV8Sb12 above 0.3 K under in situ pressure up to 46 GPa. Compared to CsV3Sb5, theoretical calculations and angle-resolved photoemission spectroscopy reveal a quasi-two-dimensional electronic structure in CsV8Sb12 with C 2 symmetry and no van Hove singularities near the Fermi level. Our findings will stimulate more research into V-based kagome quantum materials.

Angle-resolved photoemission spectroscopy of non-cuprate two-dimensional perovskite superconductor Sr2RuO4

1997 ◽  
Vol 237-238 ◽  
pp. 377-379
Author(s):  
T. Yokoya ◽  
A. Chainani ◽  
T. Takahashi ◽  
H. Ding ◽  
J.C. Campuzano ◽  
...  
Keyword(s):  
Photoemission Spectroscopy ◽  
Two Dimensional ◽  
Angle Resolved Photoemission Spectroscopy

Large thermoelectric power generated by the van Hove singularity in NaxCoO2

2007 ◽  
Vol 1044 ◽  
Author(s):  
Tsunehiro Takeuchi ◽  
Syuhei Kuno
Keyword(s):  
Thermoelectric Power ◽  
Electrical Conduction ◽  
Tight Binding ◽  
Mean Free Path ◽  
Photoemission Spectroscopy ◽  
Power Calculation ◽  
Two Dimensional ◽  
Van Hove Singularity ◽  
Range Analysis ◽  
Angle Resolved Photoemission Spectroscopy

AbstractMechanism leading to the large thermoelectric power and metallic electrical conduction observed in NaxCoO2 was investigated by means of angle resolved photoemission spectroscopy and the Bloch-Boltzmann theory. As a result of thermoelectric power calculation using the experimentally determined electronic structure under the assumptions of rigid band and constant mean free path, NaxCoO2 were found to possess the Boltzmann-type electrical conduction over a wide carrier-concentration range. Analysis using the simplest tight-binding bands revealed that the two-dimensional hexagonal lattices including the crystalline structure of the present NaxCoO2 produce a characteristic spectral conductivity leading to the large thermoelectric power and metallic electrical conduction.

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