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Anomalous Nernst Effect in the Dirac Semimetal Cd_{3}As_{2}
Tian Liang1, Jingjing Lin1, Quinn Gibson2
1Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
Physical Review Letters
|April 15, 2017
Summary
We observed a large anomalous Nernst effect in cadmium arsenide (Cd_{3}As_{2}) semimetals. This effect is closely linked to the material's unique electronic properties and suppression of backscattering.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Solid-State Physics
Background:
- Dirac and Weyl semimetals exhibit unique electronic properties.
- Cadmium arsenide (Cd_{3}As_{2}) is a material known for its ultrahigh charge carrier mobility due to Dirac nodes.
- Theoretical predictions suggest an anomalous Nernst effect in these materials under magnetic fields, linked to Berry curvature.
Purpose of the Study:
- To experimentally observe and characterize the anomalous Nernst effect in Cd_{3}As_{2}.
- To investigate the relationship between the anomalous Nernst effect and the material's transport properties.
Main Methods:
- Experimental measurement of the anomalous Nernst effect in Cd_{3}As_{2} under applied magnetic fields.
- Analysis of transport relaxation time (τ_{tr}) and quantum oscillations.
- Temperature-dependent measurements to study the onset of the effect.
Main Results:
- A large anomalous Nernst effect was observed in Cd_{3}As_{2}.
- Both the anomalous Nernst signal and τ_{tr} increased rapidly around 50 K.
- Quantum oscillations exhibited a beating effect in a magnetic field, indicating the splitting of Dirac nodes into Weyl states.
Conclusions:
- The observed anomalous Nernst effect is strongly correlated with the protection mechanism suppressing backscattering.
- The splitting of Dirac nodes into Weyl states in a magnetic field allows for the observation of Berry curvature via the anomalous Nernst effect.