Download presentation
Presentation is loading. Please wait.
1
Capri spring school, April 2009 With collaborators: P. Mehta - Princeton C. Bolech - Rice A. Jerez - NJIT, Rutgers G. Palacios - Rutgers N. Andrei - Rutgers Special Thanks: C. Yee -Rutgers Sung Po Chao Nonequilibrium transport in the Anderson model of a biased Quantum Dot
2
Goldhaber-Gordon et al, Cronenwet et al. van der Wiel et al. Conductance vs gate voltage - Kondo enhancement in odd valleys Differential conductance vs bias - Nonequilibrium dynamics T varies in the range 15-800mK Quantum Dot in and out of Equilibrium Equilibrium Nonequilibrium (Lee & Ng,Glazman & Raikh)
3
Hamiltonian to describe the system: Single Impurity Anderson model Scattering Bethe Ansatz approach: (P.Mehta, N.Andrei 06) 1. Diagonalize the Hamiltonian out of equilibrium: 2. Compute expectation value:
4
Current and Dot Occupation Current and dot-occupation operators: Expectation value expressed in terms of Bethe Ansatz density : with and given by
5
Conductance in equilibrium: Numerical results Conductance vs. gate voltage - Direct calculation from current. - Verifies Friedel SR - TBA vs SBA Von Delft, notes
6
Conductance out of equilibrium: Numerical results..2 cases Case 1: Case 2: From Kondo to mixed valence (0 refers to equilibrium Fermi surface of the leads)
7
Conductance out of equilibrium: Numerical results case 1 Obtain Tk from quadratic fit for Kondo peak nearby V=0. Observed universality for small voltage region. Conductance vs. bias voltage V : Conductance nearby zero voltage: Conductance for voltage larger than Kondo temp:
8
Conductance out of equilibrium: Numerical results case 2 Conductance vs. bias voltage : Contour plot of conductance vs source-drain voltage and gate voltage: The Kondo effect forms as is decreased, destroyed as the bias voltage is increased (M Grobis et al,PRL 100,246601)
9
Summary and Outlook Computed Nonequilibrium transport properties of Anderson impurity model. Outlook: Finite temperature/finite magnetic field. Muti-terminal quantum dot/quantum wire
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.