## 7 Comparison with Other Models  
Quite a few models are suggested in the literature for a description of defects in metallic glasses. A common shortage in most of them is the lack of understanding of their nature. However, it turns out that many of these models are quite consistent with the IT, as sketched below. [PERSON] suggested that the main properties of MGs are determined by the defects, which create shear, hydrostatic compression and/or tension (so-called \(\tau\)-, \(p\)- and \(n\)-defects) [8]. Meanwhile, the dumbbell interstitials are featured by the same combination of stresses. Figure 12 shows the changes of the Voronoi polyhedra volume (indicated by the numbers) for a dumbbell interstitial in a Cu crystal with respect to the ideal lattice. It is seen that the interstitial produces both positive and negative changes of the Voronoi polyhedra volume. In other words, the defect creates both hydrostatically compressed and hydrostatically tensioned regions. One can expect that the same should be applicable for an interstitial-type defect in the glass. Taking into account that shear stress field is one of its main characteristics, one can conclude that the defect demonstrates the properties similar to those of [PERSON]'s \(\tau\)-, \(p\)- and \(n\)-defects. It is often mentioned that supercooled liquids contain \"strings\" (\"string-like\" solitons), which become frozen in the solid glass [12; 87; 88; 89; 90; 91]. It is also sometimes said that these defects resemble the signatures of dumbbell interstitials in crystals [33; 88]. Meanwhile, the \"string\" idea is compatible with the IT since a split interstitial in the original [PERSON]'s model was considered as a string segment [13; 14]. Similar arguments can be applied for the defects viewed as \"shear transformation zones\" [3; 92], \"soft spots\" [70; 76], \"soft zones\" [92], \"flow units\" [10; 93], \"liquid-like regions\" [11], \"geometricallly unfavored motifs\" [76; 94] and \"regions with large non-affine displacements\" [3; 9; 76]. Since the region of an interstitial-type defect is characterized by the big shear susceptibility, the shear deformation of  
Figure 12: Dumbbell [001]-oriented interstitial (two red circles) and the relative changes of the volume of the Voronoi polyhedra \(\Delta V/V\) (indicated by the numbers) as compared with the ideal lattice for the atoms (shaded circles) in a copper crystal. \(\Delta V/V\)-changes are shown along the dumbbell axis, perpendicular to it and in the [111] direction. It is seen that the defect creates both positive and negative changes of the Voronoi polyhedra volume (i.e., changes of the local density) [27]. With permission from JETP Letters, 2019.  
the surrounding material upon action of the applied stress is bigger that of the matrix and contains a large non-affine component [41]. Naturally, the above terms (\"soft zones\", \"liquid-like regions\", etc.) can be applied to this region. It should be noted that these defects also contribute to the low-frequency part of the vibration spectrum of a glassy structure [76; 93] similar to what is assumed by the IT. Another approach to the understanding of defects in MGs is the \"free volume\" model, which was suggested long ago [1; 95; 96] and subjected to numerous modifications since then (e.g., Ref. [97]). In this approach, the defects are considered as regions of the reduced density (vacancy-like \"free volume\"), which affect relaxation and deformation phenomena in MGs. The premise for its popularity consists, on the one hand, in a decreased density of MGs (frozen-in \"free volume\") with respect to their maternal crystals and, on the other hand, in the existence of numerous correlations of MGs' properties with the amount of the \"free volume\" [98]. Although this model was repeatedly criticized in different directions [5; 99], it nonetheless constitutes perhaps the most popular approach. Meanwhile, it is quite compatible with the IT.