Thermoelectric Properties of Fe0.2Co3.8Sb12-xTex ... - Physics

Large linear magnetoresistance in a GaAs/AlGaAs heterostructure
Mohammed Ali Aamir, 1 Srijit Goswami, 1 Matthias Baenninger, 2 Vikram
Tripathi, 3 Michael Pepper, 4 Ian Farrer, 2 David A. Ritchie, 2 and Arindam Ghosh 1
1 Department of Physics, Indian Institute of Science, Bangalore 560 012, India.
2 Cavendish Laboratory, University of Cambridge,
J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
3 Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
4 Department of Electrical and Electronic Engineering,
University College, London WC1E 7JE, United Kingdom
Large electrical response to magnetic field is one of the key requirements in materials engineering
today. It may seem that a magnetic nature of the material is vital for this [1], but some materials
exhibit it even without magnetism at any scale. Over the last decade, it has been shown that
material inhomogeneity alone can provide a route to large magnetoresistance (MR) in non-magnetic
semiconductors [2, 3]. Interestingly, this MR also has a linear characteristic. Here, we study the MR
of a two-dimensional electron system (2DES) in a GaAs/AlGaAs heterostructure where a disordered
band-structure is induced by applying a large negative gate bias. We find that MR increases linearly
with magnetic field when the device is operated in the non-equilibrium regime with high sourcedrain
bias [4]. Remarkably, the magnitude of MR is as large as 500% per Tesla, thus dwarfing most
non-magnetic materials which exhibit this linearity. Its primary advantage over other materials is
that both linearity and the enormous magnitude are retained over a broad temperature range (0.3 K
to 10 K), thus making it an attractive candidate for on-chip magnetic field sensing.
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86, 081203 (2012),