Metal–insulator transition in manganese‐doped InSb crystals
Metal–insulator transition in manganese‐doped InSb crystals
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DOI：
10.1002/pssb.200440008
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发表时间：
2005-05
期刊：
影响因子：
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通讯作者：
S. A. Obukhov
中科院分区：
文献类型：
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作者：
S. A. Obukhov
发现具有接近p-InSb（Mn）中的金属-绝缘体转变（MIT）的临界浓度Ncr的空穴浓度的锰掺杂的InSb晶体的输运性质不同于掺杂有非磁性杂质（诸如p-Ge（Ga）、p-Si（P）和p-InSb（Ge））的半导体中的MIT。在空穴浓度p = 1-2 × 10 ~（17）cm ~（-3）范围内，在跃迁的绝缘体侧（NMn ≤ Ncr = 2 × 10 ~（17）cm ~（-3））观察到激活型导电，其能隙Δ = 7 × 10 ~（-6）-10 ~（-3）eV。因此，通常在低温和超低温下掺杂非磁性杂质的晶体半导体中观察到的可变范围跳跃电导率在p ≤ Ncr的p-InSb（Mn）中没有显示。外加磁场使Δ减小，电阻率大幅度下降（T ≤ 0.3 K，B ≥ 3 T时ρ0/ρB = 10 4）。当冷却到T = 1.5 K以下时，霍尔常数在B < 3 T时改变符号。霍尔常数符号随温度降低的变化意味着p-InSb（Mn）和用Te-p-InSb（Mn，Te）-补偿的晶体在低温下的导电性是由电子引起的。所提出的模型将p Ncr处的激活能Δ与杂质带中形成的子带之间的能隙相关联。（© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA，魏因海姆）
Transport properties of manganese‐doped InSb crystals with hole concentration close to the critical concentration Ncr of the metal–insulator transition (MIT) in p‐InSb(Mn) was found to be different from MIT in semiconductors doped with non‐magnetic impurities such as p‐Ge(Ga), p‐Si(P) and p‐InSb(Ge). On the insulator side of the transition (NMn ≤ Ncr = 2 × 1017 cm–3) in the range of hole concentration p = 1–2 × 1017 cm–3 an activation type of conductivity with energy gap Δ = 7 × 10–6–10–3 eV was observed. Thus, the usually observed variable range hopping conductivity in crystal semiconductors doped with non‐magnetic impurities at low and super‐low temperatures was not revealed in p‐InSb(Mn) at p ≤ Ncr. An external magnetic field decreased Δ and caused a giant decrease of specific resistivity (ρ0/ρB ∼ 104 at T ≤ 0.3 K and B ≥ 3 T). On cooling to temperatures below T = 1.5 K the Hall constant changed sign at B < 3 T. The change of Hall constant sign with decrease of temperature means that conductivity of p‐InSb(Mn) and crystals compensated with Te – p‐InSb(Mn, Te) – at low temperatures was caused by electrons. The proposed model associated an activation energy Δ at p ∼ Ncr with the energy gap between sub‐bands formed in the impurity band. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)