scholarly journals Spin-charge separation in a strongly correlated spin-polarized chain

2007 ◽  
Vol 76 (14) ◽  
Author(s):  
Shimul Akhanjee ◽  
Yaroslav Tserkovnyak
Keyword(s):  
Charge Separation ◽  
Strongly Correlated ◽  
Spin Polarized

Physical properties of electrically conducting and stable molecular neutral radical solid [Co(2,3-Nc)(CN)2]CH3CN (2,3-Nc = 2,3-naphthalocyanine)

2004 ◽  
Vol 08 (11) ◽  
pp. 1258-1268 ◽  
Author(s):  
Toshio Naito ◽  
Naoko Matsumura ◽  
Tamotsu Inabe ◽  
Masaki Matsuda ◽  
Hiroyuki Tajima
Keyword(s):  
Phase Transition ◽  
Magnetic Susceptibility ◽  
Physical Properties ◽  
Thermoelectric Power ◽  
Charge Separation ◽  
Energy Gap ◽  
Reflectance Spectra ◽  
Strongly Correlated ◽  
Neutral Radical ◽  
Type Transition

Solid state properties of dicyano(2,3-naphthalocyaninato)cobalt(III) neutral radical crystal, [ Co (2,3- Nc )( CN )2] CH 3 CN , were characterized by measurements of the resistivity under high pressure and under uniaxial strain, thermoelectric power, magnetic susceptibility, ESR and polarized reflectance spectra. The title compound exhibited thermally activated-type electrical conductivity along the c-axis. The room temperature (RT) resistivity ρRT along the c-axis and activation energy Ea rapidly decreased with increasing pressure. The temperature-dependent thermoelectric power S was that of a typical one-dimensional (1D) semiconductor. However the high absolute value of S suggested that this electronic system should be strongly correlated. Although the electrical resistivity exhibited monotonous temperature-dependence, the magnetic susceptibility clearly indicated a Peierls-type transition and marked fluctuation from RT. Both Peierls-type transitions and fluctuations are characteristic phenomena to 1D conductors. Furthermore ESR spectra manifested that the Peierls-type transition occurred at 100 K. The inconsistency between the electrical behavior (without a phase-transition) and magnetic behavior (with a phase-transition) indicates separation of the degrees of freedom in spin and charge (spin-charge separation) of this material. Spin-charge separation is a theoretically predicted phenomenon peculiar to the 1D conductors with strong correlation. The reflectance spectra were quantitatively explained by a 1D Hubbard model, and manifested the existence of a structural fluctuation of this material from RT. Based on these observed physical properties it is concluded that [ Co (2,3- Nc )( CN )2] CH 3 CN is a strongly correlated 1D semiconductor with a Mott(Hubbard) type energy gap and characterised with a fluctuation and spin-charge separation.

SPIN–CHARGE SEPARATION AND TOPOLOGICAL PHASE TRANSITIONS IN AHARONOV–BOHM RINGS OF INTERACTING ELECTRONS

2006 ◽  
Vol 20 (19) ◽  
pp. 2651-2655
Author(s):  
B. NORMAND ◽  
K. HALLBERG ◽  
A. A. ALIGIA ◽  
A. P. KAMPF
Keyword(s):  
Charge Separation ◽  
Spectroscopic Properties ◽  
Strongly Correlated ◽  
Conductance Peak ◽  
Band Insulator ◽  
Interacting Electrons ◽  
Interacting Systems ◽  
Ionic Hubbard Model ◽  
Aharonov Bohm ◽  
Topological Phase Transitions

We investigate the properties of strongly correlated electronic models on a flux-threaded ring connected to semi-infinite free-electron leads. The interference pattern of such an Aharonov-Bohm ring shows sharp dips at certain flux values, determined by the filling, which are a consequence of spin-charge separation in a nanoscopic system. The conductance through such a molecule or nanodevice is related directly to its spectroscopic properties, opening new experimental possibilities for probing the phenomenology of strongly interacting systems. As a further example, for a ring described by the half-filled ionic Hubbard model we show that the weight of the first conductance peak as a function of gate voltage or external flux allows one to identify the topological charge transition between a correlated insulator and a band insulator.

Sign in / Sign up

Export Citation Format

Share Document