june 4no 6-f chen_annual meeting

1、Superconductivityfrominversionasymmetric topological insulatorsF. Chen2015.06.04HPSTAROutline:p From Rashba semiconductor to topologicalinsulator BiTeX (X=I, Br, Cl)p Superconductivity of BiTeBr under high pressurep Summaryspace group P3m1Rashba Spin-orbital interaction(SOI)BiTeIStructural inversion

2、 asymmetry(SIA)K. Ishizaka, et al., Nat. Mat. 10, 521-526 (2011)O. Krupin et al., New J. Phys. 11, 013035 (2009)Inversion asymmetric topological insulator BiTeXBiTeIBiTeClSTMstudyalsoprovesthereexists Dirac Fermi surfaceWhy BiTeX?BiTeClM. S. Bahramy et al., Nat. Com. 3, 679 (2012)Y. L. Chen et al.,

3、Nat. Phys. 9, 704 (2013) Y. J. Yan et al., arXiv: 1502.07080 (2015)TheexistenceofDiracFermisurface on Te terminationTransportation measurement on BiTeClTwo hallmarks for topological surface state:1.2.Weak anti-localization effect2D property with p Berry phaseNo weak anti-localization effect3D proper

4、ty with 0 Berry phaseWhy?Surfacechargein the vacuum!Solution:High pressure!F. Chen et al, PRB 90, 201202(R) (2014)Outline:p From Rashba semiconductor to topologicalinsulator BiTeX (X=I, Br, Cl)p Superconductivity of BiTeBr under high pressurep SummaryRT of BiTeBr under HPMetal-Insulator transition0.

5、540.4814.1GPa0.4212.8GPa10.1GPa0.360.3011.1GPa9.1GPa0.240.188.1GPa0.12M. Sakano et al., PRL 110, 107204 (2013)0100r200300T(K) T0.30Two phases compete witheach other!0.240.1801020T (K)3040R (W)R (W)10.1GPa11.1GPaSame metallic phaseas before?No!RT of BiTeBr under HPInsulator-Metal transition0.615.5GPa

6、0.517.3GPa0.419.8GPa0.321.0GPa22.3GPa0.223.9GPa25.1GPa26.7GPa0.10.0050100150200250300T (K)0.615.5GPa0.5Anewmetallic17.3GPa0.419.8GPaphasewithFermi0.321.0GPa22.3GPa23.9GPa25.1GPaliquid behavior!0.20.126.7GPa0.00246810T (K)R (W)R (W)R (W)0.440.4217.3GPa0.400.380.3619.8GPa0.340.3221.0GPa0.300.280.260.2

7、422.3GPa0.220.20200040006000T2 (K2)RT of BiTeBr under HP0.040.0827.6GPa0.0328.8GPa0.0630.2GPa32.2GPa35.2GPa0.0239.8GPa41.2GPa42.6GPa43.3GPa45.8GPa50.2GPa0.0437.7GPa0.010.020.000.00050100150T (K)200250300050100150T (K)2002503000.080.0427.6GPa0.0628.8GPa0.0339.8GPa41.2GPa42.6GPa43.3GPa45.8GPa50.2GPa30

8、.2GPa32.2GPa35.2GPa0.040.0237.7GPa0.020.010.0002468100.00T (K)0246810T (K)TC doesnt change with pressure!R (W)R (W)R (W)R (W)Upper critical magnetic field of BiTeBrunder HPWHH Theory:HC2(0) = 0.693-(dHC2)/dTTcTCHall and TCof BiTeBr under HP51E2241E211E203BiTeBrHallTC1E192102030P (GPa)4050The evolution of TC with pressure is similaras that of carrier density.n (cm-3)TCPhase diagramSummaryMetal-insulator transition with pressureSuperconducting transitionPossible topological su