scholarly journals Two-channel quantum wire with an adatom impurity: Role of the van Hove singularity in the quasibound state in continuum, decay rate amplification, and the Fano effect

2009 ◽  
Vol 80 (11) ◽  
Author(s):  
S. Garmon ◽  
H. Nakamura ◽  
N. Hatano ◽  
T. Petrosky
Keyword(s):  
Decay Rate ◽  
Quantum Wire ◽  
Van Hove Singularity ◽  
Quasibound State ◽  
Fano Effect

THE VAN HOVE SINGULARITY IN HIGH Tc SUPERCONDUCTORS

1995 ◽  
Vol 09 (09) ◽  
pp. 1067-1080 ◽  
Author(s):  
M.L. HORBACH ◽  
H. KAJÜTER
Keyword(s):  
Energy Scale ◽  
Measured Temperature ◽  
Van Hove Singularity ◽  
High Tc Superconductors ◽  
Electronic Density ◽  
High Tc ◽  
Scattering Rate ◽  
Weakly Coupled ◽  
Coherence Lengths

Experimental indications for the role of the van Hove singularity (vHs) in the electronic density of states of high Tc superconductors are discussed. It is argued that (i) like the resistivity, the measured temperature and doping dependences of the normal state electronic specific heat of YBCO are consistent with the existence of a vHs and (ii) the doping dependence of Tc in the underdoped and optimally doped regimes may be accounted for mainly by a vHs. Further, we discuss the suppression of the quasiparticle scattering rate below Tc, and the coherence lengths in the hole-doped materials and NCCO. Assuming that the same mechanism for superconductivity operates in the electron-doped and the hole-doped cuprates, we argue that the bosonic mode that causes the superconductivity is strongly influenced by the doping in the overdoped regime. We further argue that this boson involves an energy scale larger than that of phonons and is only weakly coupled to the charge carriers.

Role of Van Hove singularity in high-temperature superconductors: Mean field

1991 ◽  
Vol 43 (4) ◽  
pp. 3075-3084 ◽  
Author(s):  
D. M. Newns ◽  
P. C. Pattnaik ◽  
C. C. Tsuei
Keyword(s):  
High Temperature ◽  
High Temperature Superconductors ◽  
Mean Field ◽  
Van Hove Singularity

Uniform quantum wire and quantum dot arrays by atomic hydrogen assisted MBE on patterned high-index substrates: role of atomic hydrogen in natural self-faceting

1999 ◽  
Vol 201-202 ◽  
pp. 814-818 ◽  
Author(s):  
Richard Nötzel ◽  
Hans-Peter Schönherr ◽  
Zhichuan Niu ◽  
Lutz Däweritz ◽  
Klaus H Ploog
Keyword(s):  
Quantum Dot ◽  
Atomic Hydrogen ◽  
Quantum Wire ◽  
High Index ◽  
Uniform Quantum

scholarly journals Role of Intracellular Na+ in the Regulation of [Ca2+]i in the Rat Suprachiasmatic Nucleus Neurons

2019 ◽  
Vol 20 (19) ◽  
pp. 4868
Author(s):  
Ruo-Ciao Cheng ◽  
Pi-Cheng Cheng ◽  
Yi-Chi Wang ◽  
Rong-Chi Huang
Keyword(s):  
Decay Rate ◽  
Suprachiasmatic Nucleus ◽  
Cardiac Glycoside ◽  
Spontaneous Firing ◽  
Fast Decay ◽  
Slow Decay ◽  
Central Clock ◽  
Ca2 Channels ◽  
Ionophore Monensin

Transmembrane Ca2+ influx is essential to the proper functioning of the central clock in the suprachiasmatic nucleus (SCN). In the rat SCN neurons, the clearance of somatic Ca2+ following depolarization-induced Ca2+ transients involves Ca2+ extrusion via Na+/Ca2+ exchanger (NCX) and mitochondrial Ca2+ buffering. Here we show an important role of intracellular Na+ in the regulation of [Ca2+]i in these neurons. The effect of Na+ loading on [Ca2+]i was determined with the Na+ ionophore monensin and the cardiac glycoside ouabain to block Na+/K+-ATPase (NKA). Ratiometric Na+ and Ca2+ imaging was used to measure the change in [Na+]i and [Ca2+]i, and cell-attached recordings to investigate the effects of monensin and ouabain on spontaneous firing. Our results show that in spite of opposite effects on spontaneous firing and basal [Ca2+], both monensin and ouabain induced Na+ loading, and increased the peak amplitude, slowed the fast decay rate, and enhanced the slow decay phase of 20 mM K+-evoked Ca2+ transients. Furthermore, both ouabain and monensin preferentially enhanced nimodipine-insensitive Ca2+ transients. Together, our results indicate that in the SCN neurons the NKA plays an important role in regulating [Ca2+]i, in particular, associated with nimodipine-insensitive Ca2+ channels.

The role of postsynaptic potential decay rate in neural synchrony

2003 ◽  
Vol 52-54 ◽  
pp. 707-712 ◽  
Author(s):  
Yoonsuck Choe ◽  
Risto Miikkulainen
Keyword(s):  
Decay Rate ◽  
Neural Synchrony ◽  
Postsynaptic Potential ◽  
Potential Decay

scholarly journals The role of stress anisotropy in quantum wire and quantum dot formation

2003 ◽  
Author(s):  
J.P. Silveira ◽  
M.U. Gonzalez ◽  
J.M. Garcia ◽  
L. Gonzalez ◽  
Y. Gonzalez ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Quantum Wire ◽  
Stress Anisotropy
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