Coherent quantum transport of charge density waves
Abstract
Recent experiments show oscillations of dominant period h/2e in conductance vs magnetic flux of charge density wave (CDW) rings above 77 K, revealing macroscopically observable quantum behavior. The timecorrelated soliton tunneling model discussed here is based on coherent, Josephsonlike tunneling of microscopic quantum solitons of charge 2e. The model interprets the CDW threshold electric field as a Coulomb blockade threshold for soliton pair creation, often much smaller than the classical depinning field but with the same impurity dependence (e.g., ∼n_{i}^{2} for weak pinning). This picture draws upon the theory of timecorrelated singleelectron tunneling to interpret CDW dynamics above threshold. Similar to Feynman's derivation of the Josephson currentphase relation for a superconducting tunnel junction, the picture treats the Schrödinger equation as an emergent classical equation to describe the timeevolution of Josephsoncoupled order parameters related to soliton dislocation droplets. Vector or timevarying scalar potentials can affect the order parameter phases to enable magnetic quantum interference in CDW rings or lead to interesting behavior in response to oscillatory electric fields. The ability to vary both magnitudes and phases is an aspect important to future applications in quantum computing.
 Publication:

Physical Review B
 Pub Date:
 March 2013
 DOI:
 10.1103/PhysRevB.87.115127
 arXiv:
 arXiv:1212.3020
 Bibcode:
 2013PhRvB..87k5127M
 Keywords:

 71.45.Lr;
 72.15.Nj;
 03.75.Lm;
 74.50.+r;
 Chargedensitywave systems;
 Collective modes;
 Tunneling Josephson effect BoseEinstein condensates in periodic potentials solitons vortices and topological excitations;
 Tunneling phenomena;
 point contacts weak links Josephson effects;
 Condensed Matter  Strongly Correlated Electrons;
 Quantum Physics
 EPrint:
 13 pages, 9 figures, 2 tables