Aspects of Electronic Structure Instability in Search for New Superconductors: Superconducting Boride at Liquid Nitrogen Temperature?

2008 ◽  
Vol 73 (6-7) ◽  
pp. 795-810 ◽  
Author(s):  
Pavol Baňacký
Keyword(s):  
Electronic Structure ◽  
Critical Temperature ◽  
State Transition ◽  
Chemical Potential ◽  
Liquid Nitrogen Temperature ◽  
Temperature Dependent ◽  
Nuclear Dynamics ◽  
Electron Phonon Coupling ◽  
Superconducting Compounds ◽  
Oppenheimer Approximation

It has been shown that electron-phonon coupling in superconductors induces temperature-dependent electronic structure instability which is related to fluctuation of analytic critical point of some bands across the Fermi level. The band fluctuation results in a considerable reduction of chemical potential and to breakdown of the adiabatic Born-Oppenheimer approximation. At critical temperature Tc, superconducting system undergoes transition from the adiabatic electronic ground state into the antiadiabatic state at broken symmetry, which is stabilized due to the effect of nuclear dynamics. This effect is absent in non-superconducting compounds. In a good agreement with the experimental Tc of superconducting state transition, the critical temperature of the adiabatic ↔ antiadiabatic state transition has been calculated for three different superconductors. Two hypothetical compounds, LiB and ZnB2, are predicted to be potential superconductors with Tc about 17 and 77.5 K, respectively.

Introduction

2018 ◽  
Author(s):  
Niels Engholm Henriksen ◽  
Flemming Yssing Hansen
Keyword(s):  
Schrödinger Equation ◽  
Schrodinger Equation ◽  
Degrees Of Freedom ◽  
State Level ◽  
Boltzmann Distribution ◽  
Theoretical Description ◽  
Time Dependent ◽  
Nuclear Dynamics ◽  
Molecular Reaction ◽  
Oppenheimer Approximation

This introductory chapter considers first the relation between molecular reaction dynamics and the major branches of physical chemistry. The concept of elementary chemical reactions at the quantized state-to-state level is discussed. The theoretical description of these reactions based on the time-dependent Schrödinger equation and the Born–Oppenheimer approximation is introduced and the resulting time-dependent Schrödinger equation describing the nuclear dynamics is discussed. The chapter concludes with a brief discussion of matter at thermal equilibrium, focusing at the Boltzmann distribution. Thus, the Boltzmann distribution for vibrational, rotational, and translational degrees of freedom is discussed and illustrated.

Temperature dependent electron–phonon coupling of Au resolved via lattice dynamics measured with sub-picosecond infrared pulses

2021 ◽  
Vol 129 (19) ◽  
pp. 193104
Author(s):  
John A. Tomko ◽  
Sushant Kumar ◽  
Ravishankar Sundararaman ◽  
Patrick E. Hopkins
Keyword(s):  
Lattice Dynamics ◽  
Phonon Coupling ◽  
Temperature Dependent ◽  
Electron Phonon Coupling

Temperature-dependent electronic structure and topological property of the Kondo semimetal CeFe2Al10

2021 ◽  
Vol 103 (4) ◽  
Author(s):  
T.-S. Nam ◽  
Junwon Kim ◽  
Chang-Jong Kang ◽  
Kyoo Kim ◽  
B. I. Min
Keyword(s):  
Electronic Structure ◽  
Topological Property ◽  
Temperature Dependent

An exploration of electronic structure and nuclear dynamics in tropolone. I. The X̃A11 ground state

2006 ◽  
Vol 124 (20) ◽  
pp. 204307 ◽  
Author(s):  
Lori A. Burns ◽  
Daniel Murdock ◽  
Patrick H. Vaccaro
Keyword(s):  
Electronic Structure ◽  
Ground State ◽  
Nuclear Dynamics

Superconducting State

2021 ◽  
Author(s):  
Vladimir Kresin ◽  
Sergei Ovchinnikov ◽  
Stuart Wolf
Keyword(s):  
Critical Temperature ◽  
Energy Gap ◽  
Microscopic Theory ◽  
Record Values ◽  
Theoretical Treatment ◽  
Many Body ◽  
Many Body Theory ◽  
Current State ◽  
Superconducting Compounds ◽  
Body Theory

For the past almost fifty years, scientists have been trying to explain the phenomenon of superconductivity. The mechanism is the key ingredient of microscopic theory, which was developed by Bardeen, Cooper, and Schrieffer in 1957. The theory also introduced the basic concepts of pairing, coherence length, energy gap, and so on. Since then, microscopic theory has undergone an intensive development. This book provides a very detailed theoretical treatment of the key mechanisms of superconductivity, including the current state of the art (phonons, magnons, plasmons). In addition, the book contains descriptions of the properties of the key superconducting compounds that are of the most interest for science and applications. For many years, there has been a search for new materials with higher values of the main parameters, such as the critical temperature and critical current. At present, the possibility of observing superconductivity at room temperature has become perfectly realistic. That is why the book is especially concerned with high-Tc systems such as high-Tc oxides, hydrides with record values for critical temperature under high pressure, nanoclusters, and so on. A number of interesting novel superconducting systems have been discovered recently, including topological materials, interface systems, and intercalated graphene. The book contains rigorous derivations based on statistical mechanics and many-body theory. The book also provides qualitative explanations of the main concepts and results. This makes the book accessible and interesting for a broad audience.

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