Muonium as a model for interstitial hydrogen in the semiconducting and semimetallic elements

Area of Science:

• Solid-state physics and chemistry
• Defect studies in elemental materials
• Muon spin spectroscopy applications

Background:

• Interstitial hydrogen's solid-state chemistry is largely unknown in many elemental materials.
• Hydrogen impurities profoundly influence semiconductor electronic properties.
• Muonium (a hydrogen pseudo-isotope) studies provide microscopic insights into defect centers.

Purpose of the Study:

• To document the progress of μSR studies on semiconductors and semimetals of p-block elements (Groups III-VI).
• To summarize and update findings on muonium states in Group IV elements.
• To present new spectroscopic data for Groups III, V, and VI elements, including previously unpublished results.

Main Methods:

• Muon spin rotation and resonance (μSR) spectroscopy to identify crystallographic sites and electronic structures.
• Muon spin relaxation (μSR) to characterize motional dynamics and charge-state transitions.
• Ab initio computation and experimental data for monatomic, interstitial hydrogen centers.

Main Results:

• Diverse muonium states observed in elemental semiconductors, particularly carbon allotropes.
• Interplay of site and charge state in Si and Ge under varying conditions models hydrogen's electrical activity.
• Muonium centers in B, P, As, and chalcogens (S, Se, Te) exhibit varied characteristics, including shallow molecular, deep quasi-atomic, and charge-state transitions.

Conclusions:

• μSR spectroscopy is a powerful tool for characterizing interstitial hydrogen and muonium defects in elemental solids.
• Observed muonium states offer insights into defect chemistry and electronic properties, challenging theoretical descriptions.
• Studies on metals and semimetals reveal charge screening, site preference, and quantum mobility of implanted muons.