Nuclear Magnetic Resonance Studies of the Metallic Transition in Doped Silicon

Band‐Gap Narrowing in n‐Type Moderately Doped Silicon at 300 K

“…So, the conduction band edge shift AEcz, for N d > loz5 n1r3, is found to be The values of AEC1 and AECe a t 300 K as funct.ions of Nd are given in the following Table 3. Table 2), in good agreement with experimental results [14] as discussed above. It should be concluded here that all the donor electrons are delocalized at N , w 3 x loe4 m-3.…”

“…I n these measurements, nI, increases with increasing high donor concentrations (nie > n,) and is equal to ni for very low N,, assuming that all the donors are ionized. This assumption is well supported by nuclear magnetic resonance experiments in phosphorus-doped silicon [14], where all the donor electrons are delocalized at a n impurity concentration of about 3 x loz4 m-3, in good agreement with the results of Pearson and Bardeen [15].…”

Relevance of knight shift measurements to the electronic density of states

“…A case where there is an electronic transition without further structural c hanges is that of phosphorous -doped silicon [77][78][79]. At donor concentrations (nd) greater .…”

Power-law versus exponential relaxation of 29Si nucleus spins in Si:B crystals

“…At the same time, one can expect more effective entanglement generation in the 29 Si:B crystals accordingly with estimations proposed in [5]. Early experiments focused on 29 Si:B crystals are known for high metal-like concentration of acceptors 410 18 cm À 3 as well as low concentrations [8][9][10][11][12][13]. We have studied light doped (2 Â 10 14 cm À 3 boron concentration) 29 Si crystals.…”

“…The RKKY interaction is normally observed in NMR spectra of heavy doped semiconductors (n 4 10 18 cm À 3 ) [8,9]. In our samples RKKY contribution to the linewidth of the resonance peaks can be neglected, because boron concentration was $ 2 Â 10 14 cm À 3 at T¼ 300 K. Direct magnetic dipolar interactions between two neighboring 29 Si nuclear spins in single 29 Si (99%) crystal produce coupling up to 1000 Hz corresponding to the linewidth $400 Hz (5 ppm) observed in our experiments (75% of 29 Si) (Fig.…”