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Cotunneling signatures of spin-electric coupling in frustrated triangular molecular magnets

Nossa Márquez, Javier Francisco LU and Canali, C. M. (2014) In Physical Review B (Condensed Matter and Materials Physics) 89(23).
Abstract
The ground state of frustrated (antiferromagnetic) triangular molecular magnets is characterized by two total-spin S = 1/2 doublets with opposite chirality. According to a group theory analysis [M. Trif et al., Phys. Rev. Lett. 101, 217201 (2008)], an external electric field can efficiently couple these two chiral spin states, even when the spin-orbit interaction (SOI) is absent. The strength of this coupling, d, is determined by an off-diagonalmatrix element of the dipole operator, which can be calculated by ab initio methods [M. F. Islam et al., Phys. Rev. B 82, 155446 (2010)]. In this work, we propose that Coulomb-blockade transport experiments in the cotunneling regime can provide a direct way to determine the spin-electric coupling... (More)
The ground state of frustrated (antiferromagnetic) triangular molecular magnets is characterized by two total-spin S = 1/2 doublets with opposite chirality. According to a group theory analysis [M. Trif et al., Phys. Rev. Lett. 101, 217201 (2008)], an external electric field can efficiently couple these two chiral spin states, even when the spin-orbit interaction (SOI) is absent. The strength of this coupling, d, is determined by an off-diagonalmatrix element of the dipole operator, which can be calculated by ab initio methods [M. F. Islam et al., Phys. Rev. B 82, 155446 (2010)]. In this work, we propose that Coulomb-blockade transport experiments in the cotunneling regime can provide a direct way to determine the spin-electric coupling strength. Indeed, an electric field generates a d-dependent splitting of the ground-state manifold, which can be detected in the inelastic cotunneling conductance. Our theoretical analysis is supported by master-equation calculations of quantum transport in the cotunneling regime. We employ a Hubbard-model approach to elucidate the relationship between the Hubbard parameters t and U, and the spin-electric coupling constant d. This allows us to predict the regime in which the coupling constant d can be extracted from experiment. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B (Condensed Matter and Materials Physics)
volume
89
issue
23
publisher
American Physical Society
external identifiers
  • wos:000339049700004
  • scopus:84903732948
ISSN
1098-0121
DOI
10.1103/PhysRevB.89.235435
language
English
LU publication?
yes
id
ef2edd6d-db98-4727-bc80-a0dfabf8554d (old id 4595854)
date added to LUP
2014-09-05 12:42:22
date last changed
2017-01-01 06:14:37
@article{ef2edd6d-db98-4727-bc80-a0dfabf8554d,
  abstract     = {The ground state of frustrated (antiferromagnetic) triangular molecular magnets is characterized by two total-spin S = 1/2 doublets with opposite chirality. According to a group theory analysis [M. Trif et al., Phys. Rev. Lett. 101, 217201 (2008)], an external electric field can efficiently couple these two chiral spin states, even when the spin-orbit interaction (SOI) is absent. The strength of this coupling, d, is determined by an off-diagonalmatrix element of the dipole operator, which can be calculated by ab initio methods [M. F. Islam et al., Phys. Rev. B 82, 155446 (2010)]. In this work, we propose that Coulomb-blockade transport experiments in the cotunneling regime can provide a direct way to determine the spin-electric coupling strength. Indeed, an electric field generates a d-dependent splitting of the ground-state manifold, which can be detected in the inelastic cotunneling conductance. Our theoretical analysis is supported by master-equation calculations of quantum transport in the cotunneling regime. We employ a Hubbard-model approach to elucidate the relationship between the Hubbard parameters t and U, and the spin-electric coupling constant d. This allows us to predict the regime in which the coupling constant d can be extracted from experiment.},
  articleno    = {235435},
  author       = {Nossa Márquez, Javier Francisco and Canali, C. M.},
  issn         = {1098-0121},
  language     = {eng},
  number       = {23},
  publisher    = {American Physical Society},
  series       = {Physical Review B (Condensed Matter and Materials Physics)},
  title        = {Cotunneling signatures of spin-electric coupling in frustrated triangular molecular magnets},
  url          = {http://dx.doi.org/10.1103/PhysRevB.89.235435},
  volume       = {89},
  year         = {2014},
}