Anderson Localization Length Calculator

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Model parameters

Provide the dimensionless disorder amplitude W (normalized to the hopping parameter t = 1), the electron energy E within the tight- binding band (|E| ≤ 2t), and the chain length in lattice spacings.

Enter disorder, energy, and chain length to estimate localization.

Weak-disorder approximation

Anderson localization describes exponential confinement of electronic wavefunctions due to random onsite potentials. In one dimension, perturbation theory yields the approximate localization length ξ for weak disorder:

ξ = 24 ( 4 - E 2 ) W 2

Conductance follows the scaling relation g e - L ξ , measured in units of the conductance quantum e 2/ h . The calculator reports both quantities, offering a quick check on how disorder and sample length suppress transport.

Scenario comparison

Different experiments probe localization by varying disorder strength or sample length. The table below compares a baseline case with 20 % weaker and stronger disorder to illustrate sensitivity.

Localization length and conductance versus disorder level
Scenario W ξ (sites) g
W × 0.8 0.96 104.2 0.146
Baseline W 1.20 66.7 0.050
W × 1.2 1.44 46.3 0.013

Localization shrinks rapidly with increasing disorder: doubling W cuts ξ by a factor of four. The conductance column highlights how even modest changes in ξ translate into orders of magnitude difference in transport for long chains.

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