Terahertz Zeeman spectroscopy of boron in germanium to high magnetic fields

摘要: The fundamental absorption lines of substitutional boron acceptor impurity in germanium, which lie between 1 and $3\phantom{\rule{0.3em}{0ex}}\mathrm{THz}$, now have been measured magnetic fields to $18\phantom{\rule{0.3em}{0ex}}\mathrm{T}$, greatly extending the reach both previous experiments (to $7\phantom{\rule{0.3em}{0ex}}\mathrm{T}$) theory $10\phantom{\rule{0.3em}{0ex}}\mathrm{T}$). Faraday configuration was employed with field $\mathbf{B}\ensuremath{\Vert}⟨110⟩$. Unexpected behavior has observed relating magnetic-field-induced splitting ground first two excited states (all are fourfold degenerate): (a) One pair Zeeman splits at only half rate predicted field; this continues high field. other shows a rapid increase (b) pairs emerging from state initially separate field, then, above $10\phantom{\rule{0.3em}{0ex}}\mathrm{T}$, converge, almost meeting by $18\phantom{\rule{0.3em}{0ex}}\mathrm{T}$. (c) second begins plateau dramatic decrease $9\phantom{\rule{0.3em}{0ex}}\mathrm{T}$, extrapolated become zero around $24\phantom{\rule{0.3em}{0ex}}\mathrm{T}$. Taken together, these results suggest modification existing is required, may implications for quantum computation involving impurities.