bei48482_FM

The Solid State 367 Two mechanisms contribute to the sharp rise in current. One, called avalanche mul- tiplication,occurs when a ...

368 Chapter Ten to incorporate large numbers of them in an integrated circuit and they consume rel- atively large amounts of pow ...

The Solid State 369 Positive ions U 0 a Figure 10.39The potential energy of an electron in a periodic array of positive ions. de ...

370 Chapter Ten (Sec. 3.5) directed at the crystal from the outside. [When is near a, 2a, 3a,... in length, Eq. (10.17) no longe ...

The Solid State 371 Brillouin Zones The region in k-space (here an imaginary plane whose rectangular coordinates are kx and ky) ...

372 Chapter Ten depends on k^2 , the contour lines of constant energy in a two-dimensional kspace are simply circles of constant ...

The Solid State 373 waves. For clarity we consider electrons moving in the xdirection; extending the argument to any other direc ...

374 Chapter Ten maxima at the lattice points. Since the charge density corresponding to an electron wave function ise^2 , t ...

The Solid State 375 Although there must be an energy gap between successive Brillouin zones in any given direction, the various ...

376 Chapter Ten 10.9 SUPERCONDUCTIVITY No resistance at all, but only at very low temperatures (so far) Electrical conductors, e ...

The Solid State 377 superconducting when cooled. The highest critical temperatures, as much as 134 K, are found in certain ceram ...

378 Chapter Ten on the surface of the sample whose magnetic fields exactly cancel the original field inside it. This Meissner ef ...

The Solid State 379 (a) T > Tc (b) T < Tc B B Figure 10.51The Meissner effect. (a) An applied magnetic field can exist ins ...

380 Chapter Ten type I superconductors. Because Bc 2 can be quite high (Table 10.4), type II supercon- ductors are used to make ...

The Solid State 381 10.10 BOUND ELECTRON PAIRS The key to superconductivity The origin of superconductivity remained a mystery u ...

382 Chapter Ten a Cooper pair, called the energy gapEg, is of the order of 10^3 eV, which is why superconductivity is a low-tem ...

The Solid State 383 at the critical temperature Tc, the energy gap disappears, there are no more Cooper pairs, and the material ...

384 Chapter Ten if undisturbed, and the electron scattering that leads to resistance in an ordinary conductor does not occur. A ...

Exercises 385 Here is the phase difference between the wave functions of the Cooper pairs on either side of the junction. The v ...

386 Chapter Ten What is the effect on the cohesive energy of ionic and cova- lent crystals of (a) van der Waals forces and (b) ...