Emergent Network of Narrow Transport Channels

A  new  route  for  a  metal  to  insulator  transition,  driven  by  the 

creation  of  a  network  of  narrow  channels,  has  been  discovered. 

When  Pt  is  substituted  for  Ti  in  1T-TiSe2 (panel  (a)), a  self-doped 

charge-density   wave   material,   the   resistivity   shows   a   dramatic 

increase  by  five  orders  of  magnitude  (panel  (b)).  Akin  to  a  stone 

creating cracks in an ice-sheet, the impact of Pt creates domain walls 

(panel (c),(d)) of  nanometer  size diameter that  suck  charge from  the 

bulk  leaving  a  hard  insulating  gap  in  the  bulk  (panel  (e),  scan  (1)). 

The  charges  now  confined  to  narrow  channels  interact  strongly 

forming a pseudogap, similar to a Luttinger liquid, as seen in the local 

density  of  states  by  scanning  tunneling  spectroscopy  (STM)  (panel 

(e),   scan   (3,4)),   and   further   corroborated   by   angle   resolved 

photoemission  spectroscopy  (ARPES)  that  shows  a  pseudogap 

opening up at the L-point at low temperatures.