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Title: Density matrix approach to photon-assisted tunneling in the transfer Hamiltonian formalism

The transfer Hamiltonian tunneling current is derived in a time-dependent density matrix formulation and is used to examine photon-assisted tunneling. Bardeen's tunneling expression arises as the result of first-order perturbation theory in a mean-field expansion of the density matrix. Photon-assisted tunneling from confined electromagnetic fields in the forbidden tunnel barrier region occurs due to time-varying polarization and wave-function overlap in the gap which leads to a nonzero tunneling current in asymmetric device structures, even in an unbiased state. The photon energy is seen to act as an effective temperature-dependent bias in a uniform barrier asymmetric tunneling example problem. Higher-order terms in the density matrix expansion give rise to multiphoton enhanced tunneling currents that can be considered an extension of nonlinear optics where the nonlinear conductance plays a similar role as the nonlinear susceptibilities in the continuity equations.
Authors:
 [1] ;  [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Report Number(s):
SAND-2017-11873J
Journal ID: ISSN 2469-9950; PRBMDO; 663116
Grant/Contract Number:
AC04-94AL85000; NA0003525
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 97; Journal Issue: 7; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
OSTI Identifier:
1465798
Alternate Identifier(s):
OSTI ID: 1420017