thermal enhancement of interference effects in quantum point contacts n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Thermal Enhancement of Interference Effects in Quantum Point Contacts PowerPoint Presentation
Download Presentation
Thermal Enhancement of Interference Effects in Quantum Point Contacts

Loading in 2 Seconds...

play fullscreen
1 / 24

Thermal Enhancement of Interference Effects in Quantum Point Contacts - PowerPoint PPT Presentation


  • 70 Views
  • Uploaded on

Thermal Enhancement of Interference Effects in Quantum Point Contacts. Adel Abbout, Gabriel Lemarié and Jean-Louis Pichard Phys. Rev. Lett. 106, 156810 (2011). IRAMIS/SPEC CEA Saclay Service de Physique de l’Etat Condensé, 91191 Gif Sur Yvette cedex, France.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Thermal Enhancement of Interference Effects in Quantum Point Contacts' - forrest-church


Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
thermal enhancement of interference effects in quantum point contacts

Thermal Enhancement of Interference Effects in Quantum Point Contacts

Adel Abbout, Gabriel Lemarié and Jean-Louis Pichard

Phys. Rev. Lett. 106, 156810 (2011)

IRAMIS/SPEC CEA Saclay

Service de Physique de l’Etat Condensé, 91191 Gif Sur Yvette cedex, France

interferences in one dimension
Interferences in one dimension

1d model with 2 scatterers

L

Scatterers with a weakly energy dependent transmission

slide7

SGM imaging Conductance of the QPC as a function of the tip position (Harvard, Stanford, Cambridge, Grenoble,…)Topinka et al., Physics Today (Dec. 2003)

2DEG , QPC

AFM cantilever

The charged tip creates a depletion region inside the 2deg which can be scanned around the nanostructure (qpc)

Dg falls off with distance r from the QPC, exhibiting fringes spaced by lF/2

slide8
QPC Model used in the numerical studyLong and smooth adiabatic contactSharp opening of the conduction channels

+ TIP

(Square Lattice at low filling, t=1, EF=0.1)

slide11

Resonant Level Model2 semi-infinite square lattices with a tip (potential v) on the right side coupled via a site of energy V0 and coupling terms -tc

slide12

Self-energies describing the coupling to leadsexpressed in terms of surface elements of the lead GFsMethod of the mirror images for the lead GFs. Dyson equation for the tip

  • Transmission without tip

~ Lorentzian of width

  • Transmission with tip

(Generalized Fisher-Lee formula)

Narrow resonance:

expansion of the transmission t e when is small
Expansion of the transmission T(E) when is small

(Shot noise)

Out of resonance: T0 < 1, 1/x Linear terms

At resonance: T0=1; S0=0 1/x2 quadratic terms

t 0 conductance
T=0 : Conductance
  • Out of resonance:
  • At resonance:

Fringes spaced by

(1/x decay)

Almost no fringes

(1/x2 decay)

t 0 conductance at resonance
T > 0: Conductanceat resonance
  • 2 scales:
  • Temperature induced fringes:

Thermal length:

New scale:

rescaled amplitude
Rescaled Amplitude

1. Universal T-independent decay:

2. Maximum for

Bottom to top: increasing temperature

rlm model qpc
RLM modelQPC ?
  • The expansion obtained in the RLM model can be extended to the QPC, if one takes the QPC staircase function instead of the RLM Lorentzian for T0(E).
  • The width of the energy interval where

S0=T0(1-T0) is not negligible for the QPC

plays the role of the of the RLM model

for the QPC.

slide20
Interference fringes obtained with a QPC and previous analytical results assuming the QPC transmission function

Transmission ½ without tip,

Redcurve: analyticalresults

Black points: numerical simulations