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The Dynamic Mixed Metal–Insulator Phase in Self‐Heated Needle‐Like VO 2 Single Crystals
Author(s) -
Fisher Bertina,
Kornblum Lior,
Patlagan Larisa,
Reisner George M.
Publication year - 2020
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.202000074
Subject(s) - materials science , dissipation , condensed matter physics , electrical resistivity and conductivity , insulator (electricity) , phase (matter) , metal , steady state (chemistry) , physics , chemistry , optoelectronics , thermodynamics , quantum mechanics , metallurgy
Reported herein is the mixed metal–insulator phase induced in needle‐like VO 2 single crystals by direct current (DC) electric currents applied at ambient temperature; it appears in the current‐controlled negative differential resistivity (CC‐NDR) regime of the nonlinear I – V characteristic governed by self‐heating. In this regime, the I – V characteristic is stable for R L ≥ |d V /d I | max , ( R L —the load resistance); for lower R L , portions of I – V are unstable and switching occurs between initial and final steady states (SSs). In high‐quality needle‐like VO 2 single crystals (cross‐sectional area < 2 × 10 −5 cm 2 ) the SS NDR regime is “unique,” whereas crossing from the insulating to the mixed phase I ( V ) is almost—or perfectly—smooth, the dissipation power ( P = IV ) versus current bends and this bend is accompanied by the appearance of insulating domains sliding along the metallic background in the sense of the current. The periodic domain emission, the variation of the dynamic parameters (domains’ frequency and sliding velocity) over the steady‐state NDR regime, and the energetics of the process are discussed. These results show that the process of domain emission and sliding is fairly expensive at low frequencies but there is some evidence that the process becomes more efficient at higher frequencies.