Local density of states and scattering matrix in quasi-one-dimensional systems

2002 ◽  
Vol 65 (11) ◽  
Author(s):  
Satofumi Souma ◽  
Akira Suzuki
Keyword(s):  
Density Of States ◽  
Local Density ◽  
Scattering Matrix ◽  
Local Density Of States ◽  
One Dimensional

Current Delivered by an STM Tip in Landauer-Büttiker Formalism

2012 ◽  
Vol 229-231 ◽  
pp. 1630-1634
Author(s):  
Urbashi Satpathi
Keyword(s):  
Density Of States ◽  
Local Density ◽  
Scattering Matrix ◽  
Local Density Of States ◽  
Classical Formula ◽  
Quantum Regime ◽  
A Current

When an STM tip is brought close to a nano sized sample then it can deliver (or draw) a current that is determined by the Landauer-Büttiker formalism in terms of the scattering matrix that gives partial local density of states. We show that, very paradoxically, the interference related term in this formula vanish in a quantum regime making semi-classical formula for injectance exact in some regime. We explicitly show how evanescent modes are responsible for this. This can have useful implications to experimentalists as semi-classical formulas are much simpler.

LARMOR PRECESSION TIME, WIGNER DELAY TIME AND THE LOCAL DENSITY OF STATES IN A QUANTUM WIRE

2005 ◽  
Vol 19 (05) ◽  
pp. 899-909 ◽  
Author(s):  
P. SINGHA DEO
Keyword(s):  
Stationary Phase ◽  
Density Of States ◽  
Delay Time ◽  
Quantum Wire ◽  
Local Density ◽  
Scattering Matrix ◽  
Phase Approximation ◽  
Local Density Of States ◽  
Fano Resonances ◽  
Larmor Precession

Buttiker–Thomas–Pretre (BTP) [Z. Phys.B94, 133 (1994)] proposed that the concepts behind the Larmor precession time tell us that it is possible to define exactly the local density of states (LDOS) in terms of the scattering matrix. However, we take into account evanescent modes and show that for an impurity in a quantum wire, this is in principle not exactly true. We also prove that the Wigner delay time gives correct superluminal times at the Fano resonances, in spite of the fact that the stationary phase approximation is not valid there.

scholarly journals Microscopic versus mesoscopic local density of states in one-dimensional localization

2002 ◽  
Vol 65 (12) ◽  
Author(s):  
H. Schomerus ◽  
M. Titov ◽  
P. W. Brouwer ◽  
C. W. J. Beenakker
Keyword(s):  
Density Of States ◽  
Local Density ◽  
Local Density Of States ◽  
One Dimensional
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