2007 Fiscal Year Final Research Report Summary
Thermohydrodynamics in Quantum Hall Systems
| Project/Area Number |
16540278
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics I
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| Research Institution | Hokkaido University |
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Principal Investigator |
AKERA Hiroshi Hokkaido University, Grad. School of Eng., Professor (20184129)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUURA Hidekatsu Hokkaido University, Grad. School of Eng., Associate Professor (10282683)
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| Project Period (FY) |
2004 – 2007
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| Keywords | quantum Hall effect / nonlinear transport / theory / thermohydrodynamics |
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| Research Abstract |
1. A theory of thermohydrodynamics in two-dimensional electron systems in quantizing magnetic fields is developed including a nonlinear transport regime. Spatio-temporal variations of the electron temperature and the chemical potential in the local equilibrium are described by the equations of conservation with the number and thermal-energy flux densities. The theory is applied to calculate spatial variations of these variables in various systems as described in the following.
2. Spatial distributions of the electron temperature perpendicular to the applied current are obtained in quantum Hall systems with compressible and incompressible strips at low lattice temperatures by solving equations of electron number conservation and energy conservation as well as Poisson's equation self-consistently. In the linear-response regime, variations of the electron temperature concentrate in the incompressible strips as the lattice temperature decreases. The electron temperature indicates an anti-symmetric distribution: it becomes lower than the lattice temperature in the side of a sample with a higher electrochemical potential, and higher in the opposite side. Reflecting the anti-symmetric distribution in the linear-response regime, the current density becomes highly asymmetric as the applied current increases to the breakdown of the quantum Hall effects.
3. Spatial variations of the electron temperature in the vicinity of metallic current contacts in a quantum Hall system are calculated based on thermohydrodynamics. It is shown that, at larger currents, hot spots with high electron temperatures appear at diagonally opposite corners of the sample. At smaller currents, however, the electron temperature at one of the corners is lower than the lattice temperature, while that at the other is higher than the lattice temperature.
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