Magnetoconductance anisotropy and interference effects in variable-range hopping

Medina, Ernesto; Kardar, Mehran; Rangel, Rafael

doi:10.1103/physrevb.53.7663

Cited by 13 publications

(11 citation statements)

References 27 publications

(51 reference statements)

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“…7,16 As a result of this and due to the MC anisotropy, the observed MC of the whole sample should then correspond to the overall response of these hops. It is reasonable to assume that their hopping directions remain random with respect to the orientation of the applied field.…”

Section: ͑18͒mentioning

confidence: 96%

Magnetoconductance of strongly localized electrons in variable-range hopping: Effects of spin-orbit scattering

Lin

1998

Phys. Rev. B

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The effect of spin-orbit scattering on the hopping transport of strongly localized electrons in the variablerange hopping regime is investigated analytically in both two and three dimensions. In particular, we focus on the behavior of the magnetoconductance, which is a manifestation of the quantum interference between different electron forward-scattering paths associated with a critical hop. Treating these paths independently, we obtain closed-form results for the magnetoconductance for quasi-one-and two-dimensional systems in the limit of strong spin-orbit scattering. The magnetoconductance is positive with reduced magnitude and identical periodicity compared to that without spin-orbit scattering. Moreover, a simple formula for the field strength that first saturates the magnetoconductance is provided and can directly be compared with experiments. The magnetoconductance for three-dimensional systems in a weak magnetic field of arbitrary orientations is also obtained analytically, which shows magnetoconductance anisotropy and thus enables us to determine the direction of the critical hop. Indeed, our results for the magnetoconductance which varies according to the orientation of the applied field can be potentially used as a theoretical basis for further experimental tests of the quantum interference effects for electrons in the strongly localized regime. our predictions on the behavior of the MC for a small 3D sample with respect to the varying orientations of the field can serve as an additional testing ground for the underlying quantum phase coherence phenomena of strongly localized electrons.

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Section: ͑18͒mentioning

confidence: 96%

Magnetoconductance of strongly localized electrons in variable-range hopping: Effects of spin-orbit scattering

Lin

1998

Phys. Rev. B

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“…In the case of small and positive scattering amplitudes, µ α > 0, and at zero magnetic field the problem of electron tunneling can be mapped [30][31][32][33] onto the problem of directed polymers. In the latter problem one studies the thermodynamics of an elastic string in a delta-correlated two dimensional random potential, W (x, y) that is characterized by energy functional…”

Section: Electron Transport In Variable Range Hopping Regimementioning

confidence: 99%

Giant magnetoresistance in the variable-range hopping regime

Ioffe

Spivak

2013

J. Exp. Theor. Phys.

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We predict the universal power law dependence of localization length on magnetic field in the strongly localized regime. This effect is due to the orbital quantum interference. Physically, this dependence shows up in an anomalously large negative magnetoresistance in the hopping regime. The reason for the universality is that the problem of the electron tunneling in a random media belongs to the same universality class as directed polymer problem even in the case of wave functions of random sign. We present numerical simulations which prove this conjecture. We discuss the existing experiments that show anomalously large magnetoresistance. We also discuss the role of localized spins in real materials and the spin polarizing effect of magnetic field.

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“…In contrast, the magnetotransport properties of highly disordered films, with sheet resistance R greater than the quantum resistance R Q = h/e 2 , remain poorly understood [6]. To date there is no clear consensus as to what roles film morphology [7], phase coherent hopping [8,9,10], Zeeman splitting [11,12,13], and/or spin-orbit scattering [14,15,16] play in producing the correlated insulator phase of ultra-thin metal films. Recently, however, investigators have recognized that new insights into the processes that contribute to the formation of the correlated insulator phase can be obtained through the study of metal films that undergo a superconductor-to-insulator (S-I) transition [17].…”

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confidence: 99%

Spin-orbit scattering and quantum metallicity in ultrathin Be films

et al. 2009

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We compare and contrast the low temperature magnetotransport properties of ultra-thin, insulating, Be films with and without spin-orbit scattering (SOS). Beryllium films have very little intrinsic SOS, but by "dusting" them with sub-monolayer coverages of Au, one can introduce a well controlled SOS rate. Pure Be films with sheet resistance R > R Q exhibit a low-temperature negative magnetoresistance (MR) that saturates to the quantum resistance R Q = h/e 2 . This high-field quantum metal phase is believed to represent a new ground state of the system. In contrast, the corresponding negative MR in Be/Au films is greatly diminished, suggesting that, in the presence of strong SOS, the quantum metal phase can only be reached at field scales well beyond those typically available in a low temperature laboratory. 72.15.Rn, 1 arXiv:0901.1873v1 [cond-mat.str-el]

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Magnetoconductance anisotropy and interference effects in variable-range hopping

Cited by 13 publications

References 27 publications

Magnetoconductance of strongly localized electrons in variable-range hopping: Effects of spin-orbit scattering

Magnetoconductance of strongly localized electrons in variable-range hopping: Effects of spin-orbit scattering

Giant magnetoresistance in the variable-range hopping regime

Spin-orbit scattering and quantum metallicity in ultrathin Be films

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