Electron mass in dilute nitrides and its anomalous dependence on hydrostatic pressure
G Pettinari1, A Polimeni, F Masia
1CNISM and Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, 00185 Roma, Italy.
Physical Review Letters
|May 16, 2007
Summary
Electron mass in nitrogen-diluted GaAs1-xNx shows significant pressure-induced changes due to nitrogen states. These findings reveal how nitrogen complexes affect electronic properties in gallium arsenide.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Semiconductor Physics
Background:
- Gallium arsenide (GaAs) is a crucial semiconductor material.
- Nitrogen (N) incorporation in GaAs can alter its electronic properties.
- Understanding these alterations is key for novel electronic devices.
Purpose of the Study:
- To investigate the effect of hydrostatic pressure on electron mass in N-diluted GaAs.
- To elucidate the role of nitrogen-related states in modulating electronic properties.
- To explore the pressure-induced hybridization between conduction band states and nitrogen levels.
Main Methods:
- Magnetophotoluminescence spectroscopy was employed.
- Hydrostatic pressure was applied to GaAs1-xNx samples (x=0.10% and 0.21%).
- Electron mass dependence on pressure was analyzed.
Main Results:
- Observed exceptionally large fluctuations in electron mass (up to 60%/kbar) with increasing pressure.
- Identified pressure-driven tuning of hybridization between conduction band minimum and nitrogen-related states.
- Demonstrated significant impact of nitrogen complexes on GaAs electronic properties.
Conclusions:
- The study reveals a strong dependence of electron mass on hydrostatic pressure in N-diluted GaAs.
- Nitrogen complexes play a critical role in perturbing the electronic landscape of GaAs.
- A hierarchy of nitrogen complexes influencing electronic properties is suggested.
Related Concept Videos
01:15High-Resolution Mass Spectrometry (HRMS)
The resolution of a mass spectrometer depends on the efficiency of separating ions with different ion masses. The mass of an atom is approximated to the sum of the masses of protons and neutrons inside, considering the masses of protons and neutrons as equal. However, the masses of the proton (1.6726 × 10−24 g) and neutron (1.6749 × 10−24 g) are not truly equal. There is a minor error in the expression of atomic masses relative to the simplest atom of hydrogen. For example, the mass of helium...
02:13Nuclear Binding Energy
The difference between the calculated and experimentally measured masses is known as the mass defect of the atom. In the case of helium-4, the mass defect indicates a “loss” in mass of 4.0331 amu – 4.0026 amu = 0.0305 amu. The loss in mass accompanying the formation of an atom from protons, neutrons, and electrons is due to the conversion of that mass into energy that is evolved as the atom forms. The nuclear binding energy is the energy produced when the atoms’ nucleons are bound together;...
03:10The Equilibrium Constant
Consider the oxidation of sulfur dioxide:
01:16Other Nuclides: 31P, 19F, 15N NMR
Many organic, inorganic, and biological molecules contain spin-half nuclei such as nitrogen-15, fluorine-19, and phosphorus-31. As a result, NMR studies of these nuclei have found extensive applications in chemical and biological research.
While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a high...
While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a high...
03:18Nuclear Stability
Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10−15 meters, a nucleus is quite small compared to the radius of the entire atom, which is about 10−10 meters. Nuclei are extremely dense compared to bulk matter, averaging 1.8 × 1014 grams per cubic centimeter. If the earth’s density were equal to the average nuclear density, the earth’s radius would be only about 200 meters.
To hold positively charged protons together in the...
To hold positively charged protons together in the...
00:59Atomic Nuclei: Nuclear Magnetic Moment
All atomic nuclei are positively charged. When they have a nonzero spin, they behave like rotating charges. As a consequence of their charge and spin, these nuclei generate a magnetic field (B). This, in turn, gives rise to a magnetic moment (μ), which is randomly oriented in the absence of an external magnetic field. When an external magnetic field (B0) is applied, the magnetic moment vectors can align with the field or against it in 2 + 1 orientations. A hydrogen nucleus, which is just a...