Righi Leduc Effect

The Righi-Leduc effect , also known as the thermal Hall effect , named after Augusto Righi and Sylvestre Anatole Leduc , describes the occurrence of a temperature difference in an electrical conductor through which a heat flow flows and is located in a stationary magnetic field. The temperature difference occurs perpendicular to both the heat flow and the magnetic field direction. It is a thermomagnetic effect analogous to the Hall effect .

description

If there is a temperature difference on a conductor or semiconductor in the longitudinal direction (x) and a magnetic field of the flux density perpendicular to it (z) , then a temperature difference occurs in the transverse direction (y) . It applies ${\displaystyle B_{z}}$

${\displaystyle {\frac {{\text{d}}T_{y}}{{\text{d}}y}}=R_{\mathrm {TH} }\cdot {\frac {{\text{d}}T_{x}}{{\text{d}}x}}\cdot B_{z}}$.

The thermal Hall coefficient (Righi-Leduc coefficient) depends on the material and temperature. He has the unit 1 / T (T = Tesla ) and the Hall coefficient by the relationship ${\displaystyle R_{\mathrm {TH} }}$ ${\displaystyle A_{\text{H}}}$

${\displaystyle R_{\mathrm {TH} }=\sigma A_{\mathrm {H} }}$

linked, where is the electrical conductivity of the material. ${\displaystyle \sigma }$

root cause

The Righi-Leduc effect is a thermal analogue of the Hall effect . With the Hall effect, an externally applied voltage causes an electric current to flow. The mobile charge carriers (generally electrons) are external magnetic fields are deflected transversely (perpendicular to the current direction and perpendicular to the magnetic field) by the Lorentz force , whereby a voltage builds up in this direction. In the Righi-Leduc effect, the temperature difference causes the mobile charge carriers to flow from the warmer end to the cooler end. Here, too, the Lorentz force causes a transverse deflection. Since the electrons transport heat, one side is heated more than the other. (In addition, there is also an electrical voltage in the transverse direction; this is the Nernst effect .)

Individual evidence

1. ^ Bergmann, Schaefer: Elektrizitätslehre , De Gruyter 1966, p. 487.
2. ↑ W. Kobayahi, Y. Koizumi, Y. Moritomo: Large thermal Hall coefficient in Bismuth , Appl. Phys. Lett. 100, 011903 (2012), arXiv: 1203.2237v1 [cond-mat-mtrl-sci], March 10, 2012 [1]