Two Fermi Surface States and Two Tc-Rising Mechanisms Revealed by Transport Properties in RFeP1-xAsxO0.9F0.1 (R = La, Pr, and Nd)

Abstract Thin films of topological insulators are often capped with an insulating layer since topological insulators are known to be fragile to degradation. However, capping can hinder the observation of novel transport properties of the surface states. To understand the influence of capping on the surface states, it is crucial to understand the crystal structure and the atomic arrangement at the interfaces. Here, we use x-ray diffraction to establish the crystal structure of magnetic topological insulator Cr-doped (Bi,Sb)2Te3 (CBST) films grown on SrTiO3 (1 1 1) substrates with and without a Te capping layer. We find that both the film and capping layer are single crystal and that the crystal quality of the film is independent of the presence of the capping layer, but that x-rays cause sublimation of the CBST film, which is prevented by the capping layer. Our findings show that the different transport properties of capped films cannot be attributed to a lower crystal quality but to a more subtle effect such as a different electronic structure at the interface with the capping layer. Our results on the crystal structure and atomic arrangements of the topological heterostructure will enable modelling the electronic structure and design of topological heterostructures.

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Influence of Anisotropic Scattering Along the 2D-Fermi Surface on Transport Properties in an Asymmetric-Donor-Based Molecular Crystal

MRS Proceedings ◽

10.1557/proc-328-307 ◽

1993 ◽

Vol 328 ◽

Cited By ~ 2

Author(s):

Nathanael A. Fortune ◽

K. Murata ◽

G. C. Papavassjuou ◽

D. J. Lagouvardos ◽

J. S. Zambounis

Keyword(s):

Fermi Surface ◽

Temperature Dependence ◽

Transport Properties ◽

Hall Coefficient ◽

Electronic Transport ◽

Path Length ◽

Molecular Crystal ◽

Weak Field ◽

Anisotropic Scattering ◽

Hall Conductivity

ABSTRACTWe report our results for the temperature dependence of the Hall coefficient and in-plane resistivity for the asymmetric-donor-based quasi-2D Molecular crystal τ- (P-S,S-DMEDT-TTF)2 (AuBr2)1(AuBr2)y (y≈0.75). Using a recent “geometrical representation” of the weak-field 2D Hall conductivity developed by N.P. Ong [Phys. Rev. B 43, 193 (1991)], we model the temperature dependence of these electronic transport properties in terms of the temperature dependence of the scattering path length and its anisotropy along the 2D Fermi surface.

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U(1)×SU(2) Gauge Theory of Underdoped Cuprate Superconductors

Modern Physics Letters B ◽

10.1142/s0217984998000238 ◽

1998 ◽

Vol 12 (05) ◽

pp. 173-180 ◽

Cited By ~ 8

Author(s):

P. A. Marchetti ◽

Zhao-Bin Su ◽

Lu Yu

Keyword(s):

Gauge Theory ◽

Fermi Surface ◽

Transport Properties ◽

Gauge Field ◽

Spectral Function ◽

Normal State ◽

Doping Concentration ◽

Cuprate Superconductors ◽

Low Energy ◽

Chern Simons

The U(1)×SU(2) Chern–Simons gauge theory is applied to study the 2D t–J model describing the normal state of underdoped cuprate superconductors. The U(1) field produces a flux phase for holons converting them into Dirac-like fermions, while the SU(2) field, due to the coupling to holons gives rise to a gap for spinons. An effective low-energy action involving holons, spinons and a self-generated U(1) gauge field is derived. The Fermi surface and electron spectral function obtained are consistent with photoemission experiments. The theory predicts a minimal gap proportional to doping concentration. It also explains anomalous transport properties.

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Effect of Fermi surface destruction on transport properties in underdoped cuprates

Physical Review B ◽

10.1103/physrevb.60.3629 ◽

1999 ◽

Vol 60 (5) ◽

pp. 3629-3635 ◽

Cited By ~ 4

Author(s):

Jian-Xin Li ◽

W. C. Wu ◽

T. K. Lee

Keyword(s):

Fermi Surface ◽

Transport Properties ◽

Surface Destruction ◽

Underdoped Cuprates

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Fermi Surface Mapping Using A Third Generation Light Source

MRS Proceedings ◽

10.1557/proc-437-47 ◽

1996 ◽

Vol 437 ◽

Cited By ~ 1

Author(s):

Eli Rotenberg ◽

J. D. Denlinger ◽

S. D. Kevan ◽

K. W. Goodman ◽

J. G. Tobin ◽

...

Keyword(s):

Fermi Surface ◽

Fermi Level ◽

Light Source ◽

Three Dimensional ◽

Electronic States ◽

Surface States ◽

Surface Mapping ◽

Uniform Sampling ◽

Surface Brillouin Zone ◽

Takeoff Angle

AbstractThe electronic states at the Fermi surface determine diverse properties such as magnetism, chemical bonding, and phonon-electron coupling. Using a conventional hemispherical analyzer at the ultraESCA beamline 7.0 of the Advanced Light Source, we have measured Fermi contours of the bulk and surface states of Cu(001) and Ag(001). For bulk states, we used uniform sampling in k-space by varying both the electron takeoff angle as well as the photon energy. Three-dimensional plots (in k-space) of bulk and surface states at the Fermi level can easily be achieved within one or two synchrotron shifts. Surface states, whose momentum is independent of k-perpendicular, are easily mapped if sufficiently dense angular sampling is performed. The states crossing the Fermi level at X in the surface Brillouin Zone of Cu(100) and Ag(100) are presented as examples.

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Surface levels of organic conductors in a tilted in-plane magnetic field

Zeitschrift für Naturforschung A ◽

10.1515/zna-2021-0093 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Danica Krstovska ◽

Aleksandar Skeparovski

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Fermi Surface ◽

Tilt Angle ◽

Experimental Studies ◽

Surface States ◽

Organic Conductors ◽

Magnetic Field Direction ◽

Two Dimensional ◽

Tilted Magnetic Field

Abstract Surface quantum states in quasi-two dimensional organic conductors induced by an external magnetic field tilted in the plane of the layers are obtained and analyzed. In tilted magnetic fields, these states arise from the transitions of the electrons between the closed orbits on the sides of the Fermi surface determined by the electron momentum along the magnetic field direction p B and the coordinate of the center of electron revolution Z. By far, in organic conductors, the surface states have not been studied for tilted magnetic fields. In this work, we have performed detail analyses of the surface states in a tilted in-plane magnetic field by calculating the surface energy spectrum and surface wave functions in order to address their properties and features. We find that, in a tilted magnetic field, the surface levels have higher energies compared to those at zero tilt angle but can be observed only up to a certain tilt angle. The resonant magnetic field and angular values at which the peaks in the surface oscillations should be observed are obtained. Further theoretical and new experimental studies of the surface states in a tilted magnetic field might give new insights into the surface properties of quasi-two dimensional organic conductors. Additionally, they may reveal new information about the parameters of the Fermi surface of organic conductors necessary for its reconstruction.

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