The Hall Effect of Bismuth Telluride

Eighteen years before anyone understood what an electron was or that they existed, back when the current was thought to be an incompressible fluid, Edwin Hall, while working on his dissertation, discovered that when applying a current along a thin gold leaf attached to a glass slide, there was no voltage read perpendicular to the current. Still, when the gold leaf slide was placed between the poles of a magnet, a transverse voltage appeared. He believed this phenomenon to be a new electromotive force that appeared at right angles to the primary electromotive force. He labeled this new force as the transverse electromotive force and found that it was proportional to the product of current per area and magnetic field. It was more famously known later as the Lorentz Force. Consider a stream of electrons confined to the dimensions of a solid with velocity, ~v, in the x-direction as shown in Fig. 1.1. An applied magnetic field in the z-direction will deflect the flow of electrons into the y-direction causing an unbalanced charge distribution within the solid, creating an electric field Ey. Eventually, as the charges build up on the side of the solid that is being deflected, the forces from the magnetic and electric fields balance, and the charges are no longer deflected, and a steady state exists. This is the Hall effect. Measurement of this transverse potential difference and the electrical conductivity provides a way to measure the carrier concentration and carrier type in a semiconductor or conductor. The underlying principle of the Hall effect is a potential difference created when a current-carrying material is placed with the current perpendicular to a magnetic field. This causes a deflection in the current and, in turn, causes an electric potential to appear. If you are looking for high quality, high purity, and cost-effective Bismuth telluride, or if you require the latest price of Bismuth telluride, please feel free to email contact mis-asia.

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