دانلود کتاب فرمیولوژی – نوسانات کوانتومی و نوسانات مقاومت مغناطیسی وابسته به زاویه

Conductors such as metals with high electrical conductivity exhibit large heat transfer, high optical reflectivity at the surface, and temperature-independent magnetism. These properties are predominantly determined by the electronic states on the Fermi surface. The Fermi surfaces in conductors contain a variety of microscopic information on the electronic states that lead to physical properties. Therefore, extracting this information is an important research issue for understanding the origin of the physical properties of conductors. In general, conductors with energy bands formed by many orbitals of the constituent atoms have complicated Fermi surface structures. By contrast, the Fermi surfaces of organic conductors, often cited in this Lecture Note, have very simple structures. This is because only one orbital of an organic molecule forms an energy band, and the electronic state is highly anisotropic; i.e., the electronic state is spread out only in a certain direction or plane. The physical properties of organic conductors can be easily deduced from the simple Fermi surface structures, and therefore “Fermiology” (Fermi surface study) has developed significantly in organic conductors both experimentally and theoretically. There are two promising methods to determine Fermi surfaces and energy band structures: photoemission spectroscopy and quantum oscillation measurements. In recent years, there have been significant technical developments in the former, known as angle-resolved photoemission spectroscopy. In this method, light is incident on the surface of a sample and the energy and momentum of the electrons emitted from the sample surface are measured. This allows the direct observation of the energy bands. The advantage is that the band structure can be determined over a wide energy range up to the Fermi level due to the high energy of the incident light. However, because the emitted photoelectrons are limited to those near the surface of the sample, this technique provides information on the electronic states only at the sample surface and it means that a clean surface is required. Its energy resolution is also not high. The latter method, quantum oscillation measurements resulting from Landau quantization of electronic states in a magnetic field, can provide valuable information on the electronic states very close to the Fermi level. This method is insensitive to the sample surface condition, as quantum oscillations are observed in bulk properties such as electrical resistance, magnetization, etc. Furthermore, its energy resolution is higher than that of photoelectron spectroscopy, allowing us to probe the detailed structure of the Fermi surfaces. On the other hand, owing to the geometrical structure of the Fermi surface, electrons have characteristic orbits on the Fermi surface in a magnetic field. This orbital motion causes oscillations in the resistance as a function of the magnetic field orientation. This is called the angle-dependent magnetoresistance oscillation, and the measurement has recently been established as a method to determine the Fermi surface structure in detail. The Fermi surface structure is closely related to the mechanisms of various electronic phase transitions such as superconductiviting, density wave, and electron nematic transitions. Therefore, it is very important to know the detailed structure of Fermi surfaces in order to determine the origin of electronic phase transitions. This Lecture Note focuses on these measurements and examines how the detailed structure of Fermi surfaces can be determined. Most of the content is described for low-dimensional conductors with simple Fermi surface structures. However, the content is also applicable to conductors with complex three-dimensional Fermi surface structures. This Lecture Note is written for students who have studied elementary solid-state physics after mastering quantum mechanics and statistical mechanics. The chapters contain many appendices for a better understanding. If you wish to have a general overview of the content, you can skip the appendices. It is hoped that this Lecture Note will be of assistance to those beginning their studies in this research area. The author would like to thank Prof. Toshihito Osada (University of Tokyo) for his advice on the content of Chap. 4. The author would also like to thank the members of the University of Tsukuba Press for their advice. I am grateful to Mr. Kyohei Morisada (University of Tsukuba) for careful proofreading.