Magnetic Field Suppression of the Conducting Phase in Two Dimensions

Simonian, D.; Kravchenko, S. V.; Sarachik, M. P.; Pudalov, V. M.

doi:10.1103/physrevlett.79.2304

Cited by 279 publications

(340 citation statements)

References 19 publications

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“…For ÿelds such that B H ≈ E F , the electrons are fully polarized and the resistivity saturates as expected. The temperature dependence of the resistivity begins to become insulating-like at low temperatures with the crossover temperature increasing as n decreases [243]. This is an indication that the metallic state becomes unstable as the spins are polarized.…”

Section: Experiments In a Parallel Magnetic ÿEldmentioning

confidence: 96%

Singular or non-Fermi liquids

2002

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Section: Experiments In a Parallel Magnetic ÿEldmentioning

confidence: 96%

Singular or non-Fermi liquids

2002

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“…1 In high-mobility Si metal oxide-semiconductor field-effect transistor (MOSFET), the in-plane resistivity for a system with an electron density n larger than a critical electron density n c decreases with decreasing T , indicating a metallic behavior. 2,3,4 This metallic state is completely destroyed by the application of an external magnetic field (H) applied in the basal plane when H is higher than a threshold field H c . Such coplanar fields only polarize the spins of the electrons, indicating that the spin state is significant to the high conductivity of the metallic state.…”

Section: Introductionmentioning

confidence: 99%

Magnetic-field-induced superconductor–metal-insulator transitions in bismuth metal graphite

Suzuki

Lee

et al. 2002

Phys. Rev. B

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Bismuth-metal graphite (MG) has a unique layered structure where Bi nanoparticles are encapsulated between adjacent sheets of nanographites. The superconductivity below Tc (= 2.48 K) is due to Bi nanoparticles. The Curie-like susceptibility below 30 K is due to conduction electrons localized near zigzag edges of nanographites. A magnetic-field induced transition from metallic to semiconductor-like phase is observed in the in-plane resistivity ρa around Hc (≈ 25 kOe) for both H⊥c and H c (c: c axis). A negative magnetoresistance in ρa for H⊥c (0< H ≤3.5 kOe) and a logarithmic divergence in ρa with decreasing temperature for H c (H > 40 kOe) suggest the occurrence of two-dimensional weak localization effect.

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“…The associated metal-toinsulator transition (MIT) has subsequently become the subject of intense interest and controversy [3]. While behavior similar to that of Ref.[2] has now been reported for a wide variety of 2D carrier systems such as n-AlAs, 10], and p-Si/SiGe [11,12], the origin of the metallic state and its transition into the insulating phase remain major puzzles in solid state physics.Several experiments have demonstrated the important role of the spin degree of freedom in the MIT problem, either in systems with a strong spin-orbit interaction [10,13,14], or via the application of an external magnetic field to spin polarize the carriers [15,16,17,18,19]. The latter experiments have shown that a magnetic field applied parallel to the 2DES plane suppresses the metallic temperature dependence, ultimately driving the 2DES into the insulating regime as the 2DES is spin polarized.…”

mentioning

confidence: 99%

“…Several experiments have demonstrated the important role of the spin degree of freedom in the MIT problem, either in systems with a strong spin-orbit interaction [10,13,14], or via the application of an external magnetic field to spin polarize the carriers [15,16,17,18,19]. The latter experiments have shown that a magnetic field applied parallel to the 2DES plane suppresses the metallic temperature dependence, ultimately driving the 2DES into the insulating regime as the 2DES is spin polarized.…”

mentioning

confidence: 99%

Spin–valley phase diagram of the two-dimensional metal–insulator transition

et al. 2007

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Using symmetry breaking strain to tune the valley occupation of a two-dimensional (2D) electron system in an AlAs quantum well, together with an applied in-plane magnetic field to tune the spin polarization, we independently control the system's valley and spin degrees of freedom and map out a spin-valley phase diagram for the 2D metal-insulator transition. The insulating phase occurs in the quadrant where the system is both spin-and valley-polarized. This observation establishes the equivalent roles of spin and valley degrees of freedom in the 2D metal-insulator transition.PACS numbers: 71.30.+h, 73.43.Qt, 73.50.Dn, The scaling theory of localization in two dimensions [1], which predicts an insulating phase for two-dimensional electron systems (2DESs) with arbitrarily weak disorder, was challenged by the observation of a metallic temperature dependence (dρ/dT > 0) of the resistivity, ρ, in low-disorder Si metal-oxide-semiconductor field-effect transistors (Si-MOSFETs) [2]. The associated metal-toinsulator transition (MIT) has subsequently become the subject of intense interest and controversy [3]. While behavior similar to that of Ref.[2] has now been reported for a wide variety of 2D carrier systems such as n-AlAs, 10], and p-Si/SiGe [11,12], the origin of the metallic state and its transition into the insulating phase remain major puzzles in solid state physics.Several experiments have demonstrated the important role of the spin degree of freedom in the MIT problem, either in systems with a strong spin-orbit interaction [10,13,14], or via the application of an external magnetic field to spin polarize the carriers [15,16,17,18,19]. The latter experiments have shown that a magnetic field applied parallel to the 2DES plane suppresses the metallic temperature dependence, ultimately driving the 2DES into the insulating regime as the 2DES is spin polarized. The relevance of multiple conduction-band valleys, on the other hand, is less known. Although it has been discussed theoretically that the occupation of multiple valleys may also be important [20,21], there has been no direct experimental demonstration. Here we show that the electrons' valley degree of freedom indeed plays a crucial role, analogous to that of spin. We study a 2DES, confined to an AlAs quantum well, in which we can independently tune both the spin and valley degrees of freedom. By studying the temperature dependence of ρ at various degrees of spin and valley polarization, we map out the metal-insulator phase diagram in this system at a constant density. The 2DES exhibits a metallic behavior when either the valley or spin are left fully unpolarized, and a minimum amount of both spin and valley polarization is required to enter the insulating phase.We performed experiments on 2DESs confined to modulation-doped, AlAs quantum wells of width 11 nm and 15 nm [22]. In these systems, the electrons occupy two conduction-band valleys of AlAs centered at the edges of the Brillouin zone along the [100] and [010] directions. We denote these valleys as X and Y...

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Magnetic Field Suppression of the Conducting Phase in Two Dimensions

Cited by 279 publications

References 19 publications

Singular or non-Fermi liquids

Singular or non-Fermi liquids

Magnetic-field-induced superconductor–metal-insulator transitions in bismuth metal graphite

Spin–valley phase diagram of the two-dimensional metal–insulator transition

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