Pertubation theory around nonnested fermi surfaces. I. Keeping the fermi surface fixed

A new method for studying the de Haas–van Alphen effect in steady magnetic fields has been developed in which the field is modulated at frequency ω and a signal at frequency 2 ω is generated in a pick-up coil round the specimen because of the non-linear field dependence of magnetization. The rectified 2 ω signal is proportional to d 2 M /dH 2 and so shows de Haas–van Alphen oscillations either when H is varied for fixed orientation or when the orientation is varied in fixed H if the Fermi surface is anisotropic. Because the phase of oscillation is very high (of order 10 4 π ) even very slight anisotropy will produce a few oscillations when the orientation is varied and the method is therefore particularly sensitive for studying very nearly spherical Fermi surfaces. From the oscillations with H , values of the frequency F were found for sodium, potassium, rubidium and caesium which were close to those predicted for a free-electron sphere containing 1 electron per atom, though some small systematic deviations of order ½ % were observed which may be significant. From detailed study of the oscillations produced by rotation of single crystals in fixed H it was found possible to describe the orientation dependence of F (proportional to the area of cross-section of the Fermi surface) for potassium and rubidium consistently by a series of cubic harmonics and hence to deduce the small departures of the Fermi surfaces from spherical shape. The deviations from a sphere were found to be of the order of 1 part in 10 3 for potassium and a little less than 1 part in 10 2 for rubidium; these deviations are compared with those predicted by band structure calculations. Preliminary results for sodium suggest that it is appreciably less anisotropic than potassium. Some results are also reported on the temperature and field dependence and the absolute amplitude of the de Haas-van Alphen effect, and it is also shown how the effect can be used to measure very small variations of field with position.

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What Can Positrons Contribute to High-Tc Superconductivity?

Zeitschrift für Naturforschung A ◽

10.1515/zna-1993-1-267 ◽

1993 ◽

Vol 48 (1-2) ◽

pp. 390-397 ◽

Cited By ~ 7

Author(s):

M. Peter ◽

T. Jarlborg ◽

A. A. Manuel ◽

B. Barbiellini

Keyword(s):

Fermi Surface ◽

Anderson Localization ◽

Charge Density Waves ◽

Actual Situation ◽

Many Body ◽

Fermi Surfaces ◽

High Tc ◽

Superconducting Oxides ◽

Lifetime Studies ◽

Definition Of

Abstract The positron annihilation technique has made well-known contributions to the study of Fermi surfaces in "classical" superconductors, including A15 phases where the definition of the Fermi surface has been questioned on the grounds of Anderson localization. In the case of the superconducting oxides, even more far out models were proposed, which made the clear imaging of the Fermi surface by positrons desirable. The difficulties due to the predicted weakness of the signal, and the large possibility for trapping have now been surmounted and the Fermi surface has been seen; what more can we learn from positrons?After presenting the actual situation with experiment, we will comment on enhancement and correlation and their effect on ACAR and lifetime studies. Then we explain the picture of Jarlborg and Singh of enhancement, with its recent tests for many substances. We conclude by asking the question of sensitivity of positrons to many-body effects. Ferromagnetism, antiferromagnetism, possibly charge density waves have been seen -superconductors, heavy fermions and spinons-holons would pose a problem.Stephan Berko (1924-1991) was interested in these problems and knew that better machines and better detectors would open new possibilities.

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De Haas–Van Alphen frequency variations and curvature of the Fermi surface

Canadian Journal of Physics ◽

10.1139/p70-052 ◽

1970 ◽

Vol 48 (3) ◽

pp. 375-377

Author(s):

John M. Perz

Keyword(s):

Fermi Surface ◽

Cross Sectional Area ◽

Sectional Area ◽

Surfaces Of Revolution ◽

Angular Variation ◽

Cross Sectional ◽

Fermi Surfaces ◽

Frequency Variations

The angular variation of the extremal cross-sectional area of a surface formed by revolving an arc of a circle about an axis has been calculated for various ratios of arc radius to radius of revolution. By comparing with these results experimental rotation diagrams for portions of Fermi surfaces of metals which are approximately surfaces of revolution, values of local radii of curvature averaged over an extremal orbit can be deduced.

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Fermi-surface: A package to display perspective drawings of fermi surfaces in cubic systems

Computer Physics Communications ◽

10.1016/0010-4655(82)90044-3 ◽

1982 ◽

Vol 25 (1) ◽

pp. 63-71 ◽

Cited By ~ 5

Author(s):

Pratap C. Pattnaik ◽

Philip H. Dickinson ◽

John L. Fry

Keyword(s):

Fermi Surface ◽

Fermi Surfaces ◽

Cubic Systems

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Holographic Fermi surfaces in charge density wave from D2-D8

Journal of High Energy Physics ◽

10.1007/jhep09(2021)160 ◽

2021 ◽

Vol 2021 (9) ◽

Author(s):

Subir Mukhopadhyay ◽

Nishal Rai

Keyword(s):

Dirac Equation ◽

Fermi Surface ◽

Spectral Density ◽

Charge Density ◽

Charge Density Wave ◽

Density Wave ◽

Spin Density Wave ◽

Fermi Surfaces ◽

A Charge ◽

Ionic Lattice

Abstract D2-D8 model admits a numerical solution that corresponds to a charge density wave and a spin density wave. Considering that as the background, we numerically solve the Dirac equation for probe fermions. From the solution, we obtain the Green’s function and study the behaviour of the spectral density. We begin with generic fermions and have studied the formation of the Fermi surface and where it develops a gap. In addition, we have incorporated an ionic lattice and study its effect on the Fermi surface. Then we analysed the worldvolume fermions. In this particular model we do not find Fermi surface for the dual operators.

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Fermi surface properties of PuIn3

MRS Proceedings ◽

10.1557/proc-986-0986-oo03-04 ◽

2006 ◽

Vol 986 ◽

Author(s):

Yoshinori Haga ◽

Dai Aoki ◽

Tatsuma D Matsuda ◽

Hiroshi Yamagami ◽

Yoshiya Homma ◽

...

Keyword(s):

Magnetic Properties ◽

Fermi Surface ◽

Surface Properties ◽

Flux Method ◽

Fermi Surfaces ◽

5F Electrons

AbstractWe report Fermi surface and magnetic properties of a cubic PuIn3 grown by the indium flux method. Fermi surfaces detected by the de Haas-van Alphen effect can be well explained by the band calculations assuming itinerant 5f electrons.

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Fermi-surface: A package to display perspective drawings of fermi surfaces in cubic systems

Computer Physics Communications ◽

10.1016/s0010-4655(84)82896-9 ◽

1984 ◽

Vol 35 ◽

pp. C-768

Author(s):

Pratap C. Pattnaik ◽

Philip H. Dickinson ◽

John L. Fry

Keyword(s):

Fermi Surface ◽

Fermi Surfaces ◽

Cubic Systems

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ELECTRON MAGNETIC RESONANCE FERMI SURFACE IMAGING: APPLICATIONS TO ORGANIC CONDUCTORS AND Sr2RuO4

International Journal of Modern Physics B ◽

10.1142/s0217979202013687 ◽

2002 ◽

Vol 16 (20n22) ◽

pp. 3109-3112

Author(s):

S. HILL ◽

A. KOVALEV ◽

M. M. MOLA ◽

C. PALASSIS ◽

Z. Q. MAO ◽

...

Keyword(s):

Fermi Surface ◽

Cyclotron Resonance ◽

Charge Density Wave ◽

Density Wave ◽

Organic Conductors ◽

Metallic State ◽

Surface Imaging ◽

Two Dimensional ◽

Fermi Surfaces ◽

Fermi Surface Nesting

We report detailed angle dependent studies of the metallic state microwave (40 to 200 GHz) magneto-conductivity of single crystal samples of the α- (BEDT-TTF) 2 KHg(SCN) 4 organic charge density wave conductor, and the perovskite superconductor Sr 2 RuO 4. We observe series' of resonant absorptions which we attribute to periodic orbit resonances - a phenomenon closely related to cyclotron resonance. By performing measurements on several samples, and in different electromagnetic field configurations, we are able to couple to different orbital modes (+ harmonics), which derive from deformations (warpings) of the quasi-one and quasi-two-dimensional Fermi surfaces of these compounds. These studies provide vital information concerning interlayer dispersion which, in turn, affects the Fermi surface nesting characteristics which are believed to play a crucial role in the low temperature physics of these exotic materials.

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A computer calculation of Fermi surface cross sections using the empty lattice model

Canadian Journal of Physics ◽

10.1139/p68-460 ◽

1968 ◽

Vol 46 (12) ◽

pp. 1403-1412 ◽

Cited By ~ 7

Author(s):

Roger Taylor

Keyword(s):

Fermi Surface ◽

Computer Program ◽

Cross Sections ◽

Lattice Model ◽

Computer Calculation ◽

Correct Interpretation ◽

Fermi Surfaces ◽

The One ◽

Computer Output

A computer program has been written in Fortran IV to calculate the areas of Fermi surface cross sections using the empty lattice model often referred to as the one-OPW model. The program employs the Harrison (1960) construction and will work for any structure with any Fermi radius. For hexagonal structures both the single and double zone schemes may be employed. Any plane may be selected by the user. This plane may be rotated a specified number of times about two axes and also shifted along one of the axes in order to search for extremal orbits along this axis. In applying the program to complicated Fermi surfaces a qualitative sketch of the surface may be necessary for the correct interpretation of the computer output. A copy of the deck of cards comprising the program may be obtained from the Depository of Unpublished Data.

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