Quantum spin liquids and the metal-insulator transition in doped semiconductors

Abstract

We describe a new possible route to the metal-insulator transition in doped semiconductors such as Si:P or Si:B. We explore the possibility that the loss of metallic transport occurs through Mott localization of electrons into a quantum spin liquid state with diffusive charge neutral "spinon" excitations. Such a quantum spin liquid state can appear as an intermediate phase between the metal and the Anderson-Mott insulator. An immediate testable consequence is the presence of metallic thermal conductivity at low temperature in the electrical insulator near the metal-insulator transition. Further we show that though the transition is second order the zero temperature residual electrical conductivity will jump as the transition is approached from the metallic side. However the electrical conductivity will have a non-monotonic temperature dependence that may complicate the extrapolation to zero temperature. Signatures in other experiments and some comparisons with existing data are made.

4 pages text + 3 pages Appendices, 3 Figures; v2 - References Added

References in corpus (6)

• Spin-Liquid State in the S = 1/2 Hyperkagome Antiferromagnet Na4Ir3O8
• U(1) Gauge Theory of the Hubbard Model : Spin Liquid States and Possible Application to k-(BEDT-TTF)_2 Cu_2 (CN)_3
• Low energy effective theory of Fermi surface coupled with U(1) gauge field in 2+1 dimensions
• On the stability of U(1) spin liquids in two dimensions
• Theory of a continuous Mott transition in two dimensions
• Power-law Conductivity inside the Mott gap: application to $\kappa -(BEDT-TTF{)}_{2}C{u}_2(CN{)}_3$

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• Kitaev Quantum Spin Liquids
• Fractionalization and topology in amorphous electronic solids
• Topological spin ordering via Chern-Simons superconductivity
• Lifetimes of local excitations in disordered dipolar quantum systems
• Emergent Halperin-Saslow mode and Gauge Glass in quantum Ising magnet TmMgGaO${}_4$
• Quantifying the non-Abelian property of Andreev bound states in inhomogeneous Majorana nanowires