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Title: Persistent order due to transiently enhanced nesting in an electronically excited charge density wave

Non-equilibrium conditions may lead to novel properties of materials with broken symmetry ground states not accessible in equilibrium as vividly demonstrated by non-linearly driven mid-infrared active phonon excitation. Potential energy surfaces of electronically excited states also allow to direct nuclear motion, but relaxation of the excess energy typically excites fluctuations leading to a reduced or even vanishing order parameter as characterized by an electronic energy gap. Here, using femtosecond time-and angle-resolved photoemission spectroscopy, we demonstrate a tendency towards transient stabilization of a charge density wave after near-infrared excitation, counteracting the suppression of order in the non-equilibrium state. Analysis of the dynamic electronic structure reveals a remaining energy gap in a highly excited transient state. In conclusion, our observation can be explained by a competition between fluctuations in the electronically excited state, which tend to reduce order, and transiently enhanced Fermi surface nesting stabilizing the order.
 [1] ;  [2] ;  [3] ;  [3] ;  [4] ;  [5] ;  [3] ;  [5] ;  [2] ;  [1]
  1. Univ. Duisburg-Essen, Duisburg (Germany); Freie Univ. Berlin, Berlin (Germany)
  2. Freie Univ. Berlin, Berlin (Germany); Fritz-Haber-Institut der MPG, Berlin (Germany)
  3. Geballe Lab. for Advanced Materials, Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  4. Geballe Lab. for Advanced Materials, Stanford, CA (United States)
  5. SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2041-1723
Nature Publishing Group
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
74 ATOMIC AND MOLECULAR PHYSICS; physical sciences; condensed matter
OSTI Identifier: